Hacking The Case Interview

Hacking the Case Interview

Case interview cheat sheet & study guide

Looking for a case interview cheat sheet or study guide to help you prepare for your upcoming consulting interviews?

Download our Case Interview Cheat Sheet and Study Guide , which covers all of the most important things you need to know. If you are looking to read the case interview cheat sheet in plain text, we’ve included all of the text below.

This case interview cheat sheet covers:  

What is a case interview?

What do case interviews assess?

What is the structure of a case interview?

What are the common types of cases?

What formulas do you need to know for case interviews?

What numbers do you need to know for case interviews?

What are some case interview tips?

If you’re looking for a step-by-step shortcut to learn case interviews quickly, enroll in our case interview course . These insider strategies from a former Bain interviewer helped 30,000+ land consulting offers while saving hundreds of hours of prep time.

A case interview is a 30- to 45-minute exercise that places you in a hypothetical business situation in which you and the interviewer work together to develop a recommendation or answer to a business problem.

  • How can Walmart increase its profitability?
  • How can Nike increase customer retention?
  • How should Apple price its new smartphone?

A case interview assesses five criteria:

1.   Logical, structured thinking : Can you structure complex problems and ideas in a clear and organized way?

2.  Analytical problem solving: Can you analyze and interpret data to draw the right conclusions?

3.  Business acumen : Do you have a strong understanding of business fundamentals and good business judgment?

4.  Communication skills : Can you communicate clearly, concisely, and articulately?

5.  Personality and cultural fit : Are you a good fit for the work culture of the firm you are interviewing with?

All case interviews follow seven major steps:

1.  Understand the case background : Take notes while the interviewer reads you the case information. Pay particularly close attention to the context, company, and objective.

2.  Ask  clarifying questions : If necessary, ask 1 – 3 questions to clarify the objective of the case, understand the company better, or understand an unfamiliar term.

3.  Structure a framework : Structure a framework to break down the complex business problem into simpler, smaller components. A framework is a tool that organizes different ideas into major categories. Present your framework to the interviewer. Make sure that your framework is MECE .

M utually E xclusive: None of the parts of your framework overlap with each other

C ollectively E xhaustive: All of the parts of the framework account for everything you need to know to solve the case with no major areas missing.

4.  Start the case : How the case will start depends on whether the case is an interviewer-led case or a candidate-led case .

Interviewer-led case : The interviewer will be steering and controlling the direction of the case. They will explicitly point you to which questions to answer.

Candidate-led case : You will be driving the direction of the case. You will propose what area of your framework to start in, what questions you want to answer, what analyses you want to do, and what the next step of the case is.

5.  Solve quantitative problems : There are three major types of quantitative problems you could be asked in case interviews.

Market sizing or estimation questions : You will be asked to calculate the size of a particular market or estimate a particular figure. You may need to make your own assumptions on what number to use or the interviewer may provide you with the data.

Profitability or breakeven questions : You will be asked to calculate the expected profitability of a company or investment decision. You could also be asked to calculate the conditions necessary for a company to break even .

Charts and graphs questions : You will be asked to interpret data from various charts or graphs . These can include bar charts, pie charts, line graphs, scatterplots, bubble charts, and waterfall charts.

6.  Answer qualitative questions : There are two major types of qualitative questions you could be asked in case interviews.

Brainstorming questions : You will be asked to brainstorm a list of ideas for a particular problem or question.

Business judgment questions : You will be asked for your opinion on a business issue or a strategic decision.

7. Deliver a recommendation : Present your recommendation and provide the major reasons that support it. Then, propose potential next steps that you would take if you had more time.

Profitability case : A company is experiencing a decline in profits or profitability and is trying to identify what is causing the decline and what they should do about it.

How to solve:  

  • Identify the driver behind the decline in profitability, whether it is from a decline in revenue, increase in costs, or both
  • Understand what is causing this by looking at customer needs, competitor moves, and market trends
  • Identify ways to improve profitability

Growth strategy case : A company is trying to decide how to best grow its business.

  • Determine whether the company is looking to grow organically or inorganically
  • For organic growth, consider growth through existing revenue sources and new revenue sources
  • For inorganic growth, consider potential acquisitions and partnerships

Market entry case : A company is trying to decide whether they should enter a particular new market.

  • Determine whether the market is attractive
  • Assess the competitive landscape
  • Determine if the company has the capabilities to enter
  • Estimate the expected profitability from entering

Merger & acquisition case : A company is trying to decide whether or not they should acquire or merge with a particular company.

  • Determine whether the company is attractive
  • Assess potential synergies and risks
  • Estimate the financial implications

New product case : A company is trying to decide whether or not they should develop and launch a particular new product.

How to solve:

  • Determine whether the market that the product targets is attractive
  • Assess whether the product meets customer needs and is superior to competitor products
  • Determine whether the company has the capabilities to successfully develop and launch the product
  • Estimate the expected profitability from launching the product

Pricing case : A company is trying to decide the best way to price a particular product or service.

  • Determine the cost to produce the product. This is your minimum price.
  • Estimate the customer’s maximum willingness to pay by quantifying the value the product provides. This is your maximum price.
  • Investigate the price that competitors are setting for similar products. This will help you determine the optimal price between your minimum and maximum price.

Profit Formulas

  • Profit = Revenue – Costs
  • Revenue = Quantity * Price
  • Costs = Total Variable Costs + Total Fixed Costs
  • Total Variable Costs = Quantity * Variable Costs
  • Profit = (Price – Variable Costs) * Quantity – Total Fixed Costs

Investment Formulas

  • Return on Investment = Profit / Investment Cost
  • Payback Period = Investment Cost / Profit per Year

Operations Formulas

  • Output = Rate * Time
  • Utilization = Output / Maximum Output

Market Share Formulas

  • Market Share = Company Revenue in the Market / Total Market Revenue
  • Relative Market Share = Company Market Share / Largest Competitor’s Market Share

General Statistics

  • Global population: 8 billion
  • Average household size: 2.5 people per household
  • Average life expectancy: 80 years

Country Population Statistics  

  • United States: 320 million
  • Canada: 40 million
  • Mexico: 125 million
  • Brazil: 200 million
  • United Kingdom: 60 million
  • Germany: 80 million
  • France: 60 million
  • China: 1.4 billion
  • India: 1.4 billion
  • Russia: 150 million
  • Japan: 125 million
  • Australia: 25 million

Tip #1 - Make sure you understand the business problem and objective : Answering or addressing the wrong business problem is the quickest way to fail a case interview.

Tip #2 - Don’t rely on using memorized frameworks : Interviewers can tell when you are regurgitating memorized information and not thinking critically.

Tip #3 - Structure your approach before doing any math calculations : This helps you avoid making unnecessary calculations or reaching a dead-end.

Tip #4 - Talk through your calculations out loud : This decreases the likelihood of making a mistake and helps the interviewer follow what you are doing

Tip #5 - Structure your answer to qualitative questions : Use a simple two-part framework such as internal/external, short-term/long-term, or economic/non-economic.

Tip #6 - Answer “so what?” after every question : Throughout the case, connect each of your answers back to the case objective. What implications does your answer have on the overall business problem?

Tip #7 - Have a firm recommendation : Do not have a flimsy recommendation that switches back and forth between two different recommendations. Pick one and provide support.

Tip #8 - Be 80/20 : You will not have time to answer every single question. Focus on the most important questions that have the greatest impact on your answer. This is the 80/20 principle which states that 80% of the outcome comes from 20% of your effort.

Tip #9 - Be coachable and easy to work with : Interviewers look for people that they would personally want to have on their team. Demonstrate that you would be a great teammate.

Tip #10 - Be enthusiastic : Interviewers want to hire candidates that love their job and will work hard. Displaying enthusiasm shows you are passionate about consulting and working at the firm.

Check out our complete list of case interview tips .

Learn Case Interviews 10x Faster

Here are the resources we recommend to learn the most robust, effective case interview strategies in the least time-consuming way:

  • Comprehensive Case Interview Course (our #1 recommendation): The only resource you need. Whether you have no business background, rusty math skills, or are short on time, this step-by-step course will transform you into a top 1% caser that lands multiple consulting offers.
  • Hacking the Case Interview Book   (available on Amazon): Perfect for beginners that are short on time. Transform yourself from a stressed-out case interview newbie to a confident intermediate in under a week. Some readers finish this book in a day and can already tackle tough cases.
  • The Ultimate Case Interview Workbook (available on Amazon): Perfect for intermediates struggling with frameworks, case math, or generating business insights. No need to find a case partner – these drills, practice problems, and full-length cases can all be done by yourself.
  • Case Interview Coaching : Personalized, one-on-one coaching with former consulting interviewers
  • Behavioral & Fit Interview Course : Be prepared for 98% of behavioral and fit questions in just a few hours. We'll teach you exactly how to draft answers that will impress your interviewer
  • Resume Review & Editing : Transform your resume into one that will get you multiple interviews

Land Multiple Consulting Offers

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Case interview math (mental math) tools, formulas and tips.

consulting case study calculation

Case Interview Math (Mental Math) Tools, Formulas and Tips

Consulting case interview mental math practice is a must as part of one’s overall consulting case interview preparation. All management consulting firms, and certainly McKinsey, BCG and Bain, expect candidates to be very comfortable with quantitative data, statistics, and the ability to make decisions and client recommendations based on data.

Management consultants at firms like McKinsey, BCG, Bain, Deloitte spend a lot of time working with numbers, charts, calculations, financial models in excel and other math work, often mental math work. So any consulting case interview mental math test, and there are really multiple mental math tests scattered throughout the consulting case interview process is something you have to be well prepared for.

This does not mean that you need to have a math degree to have the right level of consulting case interview mental math skills. But you do need to know what is expected of you and you do need to practice mental math a lot.


Bonus tutorial download, 20 brain teasers with answers and explanations.

consulting case interview math mental math-3

How is consulting case interview mental math different from academic math?

Because management consulting is all about solving difficult problems, usually under extreme pressure, the case interviewer is expecting a candidate to approach math problems in a specific way. In academic settings the most important element of solving math problems is accuracy. Accuracy is also very important for case interview math but management consultants usually work under extreme time pressure. And so answers are often required to be close enough to guide towards the “right” recommendation, versus being 100% accurate.

For example, imagine you are asked to calculate the market size for baby diapers for sensitive skin in Singapore. If this was a problem within an academic setting you would be expected to give an accurate answer correct to the decimal point. In consulting case interview settings you will have to make many educated estimations to arrive at, hopefully, a close enough answer. And then you will be expected to do what we call a sanity check to ensure that your answer actually makes sense.

Let’s take a look at an example from a real McKinsey engagement, mentioned by one of our trainers, Kevin P. Coyne. In case you don’t know, Kevin is a former McKinsey worldwide strategy practice co-leader and he leads The Consulting Offer II , which you can access if you join our Premium membership or FIRMSconsulting Insider level.

In this example, Kevin mentioned serving a large bank and during initial interviews with employees of the bank, Kevin’s team noticed that 100% of the profit for that bank was coming from one business unit. That does not mean that all other business units were operating at a loss. But combined all other business units of that bank had zero profit. So the bank was dependent on this one unit to generate all their profits.

Kevin’s team further uncovered that a lot of clients that the unit served were really old. To give a more accurate answer on how bad the situation was Kevin’s team selected only 1 letter in the alphabet and studied the age of all the clients whose name started from that letter, let’s say it was letter B.

This exercise uncovered that within the next 5 years that bank would lose something like half of its clients. And it does not mean the bank will have those clients for 5 years and then they will disappear. No, the clients will start dying now and within 5 years the client base will be about half smaller than now.

And younger people were not interested in that type of service. Doing the same analyses for all clients within the unit would be cost-prohibitive and will take significantly longer, and the limited analysis conducted was more than enough to understand that the bank was in serious trouble and drastic action was required.

This is a great example of how math in real consulting settings is often focused on getting close enough/good enough answers fast and cheap. And as a great management consultant, you will need to have strong enough business judgment to know what is good enough and what is required and to never waste the client’s money and other resources on unnecessary analyses.


A comprehensive estimation cases guide, what do you mean by case interview math.

Strengthening your mental math and written math skills is one of the most important elements of preparing for case interviews.

As part of a case interview process, your mental and written math skills will be tested in multiple ways. If you are strong in academic math you are in a good place. However, the style of math used during case interviews is quite different vs. math problems in the academic context, as we discussed above, and takes time to get comfortable with.

Some examples of what case interview math test can include:

Case interview math test can include word problems . Word problems used as part of case interviews are similar to the type of word-based problems you practiced for as part of your GMAT preparation or preparation for other standardized tests. And such a case interview math test may or may not include a business-based context.

consulting case interview math mental math-2

Case interview math can be tested during a full case . In fact, full cases almost always test math along with other skills. For example, coming back to the example above, you may be asked to estimate the market size for diapers for sensitive skin babies in Singapore as part of a full case of your client considering entering the Singapore market. As part of the case, you may also be asked to work with many graphs and charts, which we refer to as data cases . We cover data cases extensively in The Consulting Offer , our flagship program where we help real candidates prepare for interviews with McKinsey, BCG, Bain, Deloitte, etc. You can track candidates’ preparation at various stages, all the way from networking, editing resume and preparing for standardized tests to getting an offer and deciding if they should accept an offer. You can track Ritika joining McKinsey Chicago, Jen joining Bain Boston, Assel joining McKinsey Europe after 5 years out of the workforce and with no prior work at MBB (never before been done), Sanjeev joining BCG, Alice joining McKinsey NYC and much more.

Mental math is also tested as part of case interview math tests. In fact, it is tested a lot as part of the case interview process. You will be required to do math in your head and very fast. This is often one of the most difficult components of a case interview for candidates. The Consulting Offer will help you prepare.

Standard math such as multiplication, division, fractions, percentages, and other concepts are routinely tested. Case interview math tests are usually baked into a case and math is just a component to finding a solution within a specific business context.

In all examples of case interview math above, speed and relative accuracy matter. And the use of calculators is not allowed. So it is crucial to practice and be ready to handle case interview math tests fast, accurately, and without a calculator.

Consulting case interview math formulas

Revenue  = Volume x Price

Cost  = Fixed cost + Variable cost

Profit  = Revenue – Cost

Profit margin / Profitability  = Profit / Revenue

Return on Investment (ROI)  = Annual profit / Initial investment

Breakeven / Payback Period  = Initial investment / Annual profit

EBITDA  = Earnings Before Interest Tax Depreciation and Amortization. EBIDTA is essentially profits with interest, taxes, depreciation and amortization added back to it. It’s useful when comparing companies across various industries.


Bonus download, proven strategies for effective leadership and results, fast mental math: rounding numbers.

What will help you become faster in doing mental math during consulting case interviews is rounding numbers. For example, ~82 million population of Germany becomes 80 million, ~46.7 million population becomes 45 million. The key to rounding numbers is to round them carefully, in a way that does not distort too much the final answer. A good guideline to follow is not to round by more than 10%. It is also helpful to round both up and down as you are working through the case, so the effects, to some degree, cancel each other out. At the end also make sure you check if your answer actually makes sense.

Fast mental math: dealing with large numbers

The key to dealing with large numbers, like 200 million, for example, is to remove zeros and then add them back later. Use labels (m,k,b) to help you keep track. So if you have 200 million, it becomes 200 m to help you remember that it is millions. 200,000 will be 200k. 10 billion will become 10 b. The key to achieving fast mental case interview math is to simplify. For example, 5 x 30 million becomes 5 x 3 = 15 with 7 zeros.

consulting case interview math mental math fast math

Fast mental math: break down numbers into smaller parts

When dealing with case interview math, another trick that will help you work through the problem faster is breaking down numbers into smaller parts. For example, 14 x 6 = (10 x 6) + (4 x 6) = 84.

Fast mental math: subtracting from numbers with 1 followed by zeros

This is another trick for faster case interview math. Again, simplify. 1000-536 becomes 999-536+1 = 464.

Fast mental math: group numbers into multiple of 10 (addition)

Another trick for fast case interview math is to group numbers into multiple of 10 (for addition). 3+7 + 4 + 6 +13 +7 +21 becomes 10 + 10 + 20 + 21 = 61.

Other tips to achieve fast case interview math (mostly mental math) during a consulting case interview

Here are a few tips to keep in mind to help you perform better during a consulting case interview when it comes to case interview math (and mostly mental math).

  • At the beginning of the case ask your interviewer if it is ok to round numbers. Most of the time they will say yes and it will make math calculations much easier and faster.
  • Do not rush. If you make a mistake it will take you even longer to fix it. This is if you even catch your mistake. You may also catch your mistake by the time when the interviewer will not give you an opportunity to fix it. And case interview math mistakes can be very embarrassing and lead to a completely wrong recommendation. Of course, there is a lot of time pressure during consulting case interviews so do not take any longer than you need. You need to find a good balance. This comes with a lot of practice. We provide a lot of opportunities for you to practice case interview math. Some full cases are provided below and you will find more on our YouTube channel. And, of course, you can unlock access to all candidates and seasons of The Consulting Offer when you become Premium member (more details below).
  • Do not be afraid to write things down when you feel you need it.
  • Keep your writing organized. Let say you are estimating how many cars will be purchased in Germany in 2020. As you are putting down numbers for each element of your equation keep it neat and organized so you don’t get confused and it will also help you avoid silly mistakes.
  • Do not state your answer to an interviewer as a question. Be confident in your answer.
  • As part of your preparation refresh key math topics like ratios, fractions, percentages, averages, and probability.  Khan Academy  is a great place to refresh your math skills. And you will have more than enough opportunities to practice fast mental case interview math as you go through various candidates and seasons within The Consulting Offer (part of  Premium membership).

Practice consulting case interview math / mental math with full cases

As you work through the cases remember to focus on all elements of good case performance, not just math. People usually underestimate how important other elements of case interview preparation are, including FIT. And only realize after being rejected that the elements they ignored during preparation were the reason for the rejection. Learn from the mistakes of others. Take all elements of case interview preparation seriously.


This case is a McKinsey style case, of medium level difficulty. It should take you 15-20 minutes to solve this case.

The question is given upfront, at 2:02. The part in black is the part the interviewer would share with you and a part in grey is the part interviewer may share as the case progresses. The interviewer wants to see if the interviewee understands the case and asks the right questions.

The case question is quite explicit but even so we will show you how you can adjust the case and make the case more explicit.

Everything rests on the key question. If anything is not part of the key question, ignore it. Even though lots of information is provided, take time to understand and set up the case.

Always show why information is needed, and show progress so the interviewer is they are willing to provide more information. It is a barter. And always use the case information provided and the appropriate language to push the case forward.


We did this recording a few months after we completed the training with Rafik (TCO I). This is one of the most complex market entry cases we had to put together. It has elements of operations, elements of pricing, elements of costing and, obviously, elements of market entry. And it is probably the most difficult market entry case we can do because most market entry cases that most interviewers focus on have a strong market attractiveness element, market profitability element. But very few people actually look at the operational issues of entering the market. And it does not matter who you are interviewing with: Bain, BCG or McKinsey. The bulk of the focus usually goes towards analyzing the market worthiness but not a lot on the operational issues. So we decided, in this case, to flip it around and give this case a strong operational theme.


Operations cases can be tackled in two ways: strategy and operations and within operations from productivity and the supply chain side. This case uses the supply chain side.

This case is candidate-led. As we mentioned above, candidate-led cases are much harder than interviewer-led cases. That is why we at FIRMSconsutling place so much more emphasis on teaching you how to lead cases vs. relying on the interviewer to lead. This will be considered an operations case. Pay attention to a very insightful brainstorming at 14:50 which includes at least one idea you most likely would not come up with if you were solving this case before watching this video.

What else can I do to improve my case interview math?

Mental math is a muscle. But most of us do not exercise it enough once we leave school. So your case interview preparation needs to include math training.

First refresh your knowledge and ability to calculate basic multiplications, divisions, additions, and subtractions, without a calculator. The Consulting Offer program (a part of Premium membership) includes ongoing opportunities to practice this. We also have many cases available for free on the FIRMSconsulting YouTube channel to get you started.

And there are other tools you can use for case interview math prep.

Khan Academy has some resources that you may find helpful. Here are some helpful links:

  • Percentages
  • Scientific notation
  • Additions and subtractions
  • Multiplications and divisions

You will need to regularly practice to get comfortable with mental and written math. Case interview math tests require you to do all math calculations fast and accurately. We recommend working through a few sessions of The Consulting Offer a day to ensure multiple opportunities to practice math and other skills you need to give yourself the highest chance to get an offer from firms like McKinsey, BCG, Bain, Deloitte, etc.

Go through a few sessions every day and you will start feeling more comfortable over time not just with case interview math but with your resume, networking, estimations, brainstorming, answering FIT questions in a way that answers what the interviewer is REALLY asking you.

You will also develop or strengthen the ability to lead and handle difficult cases, and the ability to develop your own framework uniquely tailored to solve a particular case, and much more. View it as an investment in skills that will serve you for the rest of your life vs. just searching for tips and tricks to get an offer from McKinsey, BCG, Deloitte, et al.

Additionally, some candidates found the following tools helpful as supplemental materials along with The Consulting Offer. We have not tested those tools but are sharing them in case you would like to explore them.

Mental math games (Android). This one is similar to the mental math cards challenge app on iOS (below).

Mental math cards challenge app (iOS). This mobile app is a good choice if you are an iOS user.

Magoosh’s Mental Math Practice – Arithmetic Flashcards (iOS + Android). And here is another free math app that uses flashcards. And it allows you to track your progress as you study.

MConsultingPrep: math drills

Preplounge: mental-math (registration required)

Case Interview: calculations   (registration required)

How FIRMSconsulting can help me?

You will need to get comfortable doing calculations fast and accurately. And this comes with a lot of practice. If you will be using The Consulting Offer to prepare for your consulting case interviews you will have what seems to be never-ending opportunities to practice mental and written math as part of the full cases and as part of particular questions such as estimations, etc.

Management consulting jobs are very competitive, and working with FIRMSconsulting can mean the difference between getting an offer, or multiple offers, from your target firms and barely getting an offer from the company you hoped you never would need to settle for. And the latter example is something I, unfortunately, observed many of my MBA classmates settled for.

When it comes to case interview math The Consulting Offer program, all 5 seasons of it and counting, with various candidates, includes everything you need to master not just case interview math, but all key aspects of consulting case interviews.

Don’t miss out by investing your time with general math drills when you can practice real-world case interview math examples while being taught by former consulting partners.

If you want the most comprehensive guidance for consulting case interviews math, and other aspects of case interview preparation, so you go to your interviews confidently, become a Premium or FC Insider level member now. And if you still have questions contact FIRMSconsulting ( [email protected] ) to find out why candidates even from top schools like Harvard, Stanford, and MIT choose us when they need consulting case interview preparation help, and stay with us for years and years once they get coveted jobs at McKinsey, BCG, Bain, Deloitte, etc.

WHAT IS NEXT? If you have any questions about our membership training programs (StrategyTV.com/Apps & StrategyTraining.com/Apps) do not hesitate to reach out to us at support @ firmsconsulting.com. You can also get access to selected episodes from our membership programs when you sign-up for our newsletter above or here . Continue developing your  strategy skills .

Cheers, Kris

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Case interview resume template used in The Consulting Offer . Offers from McKinsey, BCG, Bain et al.

Overall approach used in well-managed strategy studies PDF guide

The Ultimate Guide to the Consulting Case Interview – With Examples

This guide, written by a former McKinsey consultant and Wharton MBA, breaks down the management consulting case interview into comprehensible parts with relevant, realistic examples at every turn.

Tracy V.

By  Tracy V.

Posted March 12, 2024

consulting case study calculation

Featuring Ben L.

Mastering the Case: Frameworks & Structuring

Wednesday, april 17.

6:00 PM UTC · 60 minutes

Table of Contents

While the consulting case study interview may seem daunting at first, most cases follow a typical song-and-dance. Once you get a hang of it, prepping feels much more manageable. The first part of this guide will give a broad overview of the case interview. The second part will break out the typical structure of an interviewee-led case. The last part will dive into each component, with tips and suggestions for preparing. Note that some firms may have their own specific case interview style. Be sure to familiarize yourself with your target firms’ interview processes before the time comes to recruit.

Case interviews involve tackling a business issue or problem faced by a company (the client). These interviews allow consulting firms to gauge candidates’ ability to perform the job. Specifically, firms are testing whether candidates can:

  • Think in a structured and creative way
  • Analyze and interpret new information
  • Communicate persuasively and succinctly

Most firms conduct interviewee-led cases, as outlined in the guide below. In these cases, the candidate is expected to drive the case forward by asking the interviewer for data or information relevant to forming the recommendation. A few firms, most notably McKinsey, are interviewer-led, meaning that the interviewer will be the one guiding the discussion.

Below are a few common types of cases that you can expect to receive. Some cases can be several types all in one (lucky you!):

  • Profitability - Determine cause for profit decline and / or ideas for increasing profit; you will rarely get a standalone profitability case – It will usually be rolled up in another case type
  • Growth - consider strategies for company growth; could be through sales or market share
  • Market Entry / New Business - Assess attractiveness of entering new geography / business / sector and method for entering
  • Due Diligence / M&A - Assess attractiveness of purchasing / acquiring a company or business; client can be another company or a financial sponsor
  • Competitive Response - Address a competitor’s recent action (e.g., new acquisition, change in pricing strategy)
  • Non-Traditional - Similar to the other cases but the client (non-profit, NGO, education-focused entity) has different objectives than a typical corporate company

Case Interview Components

  • Prompt: Interviewer reads aloud the case while the interviewee takes notes
  • Recap: Interviewee provides a high-level summary of the case and confirms accuracy of information written
  • Clarifying Questions: Interviewee asks 2-3 high-level questions
  • Structuring (<2 minutes): Interviewee takes a few minutes create a roadmap for approaching the case
  • Framework Presentation (2-3 minutes): Interviewee reviews the structure with the interviewer, who may have follow-up questions. Interviewee then moves the case forward by asking for additional information
  • Brainstorming: Interviewee is expected to list out several solutions or ideas (e.g., cost drivers for an industry, ways to increase sales)
  • Exhibits: Interviewee will be given data in forms such as graphs or charts and expected to provide high-level insights
  • Math: Interviewee will be asked to perform a calculation with the new information or using data from the exhibits. Oftentimes, interviewee is not given enough information and must ask for the relevant data
  • Synthesis and Recommendation (2-3 minutes) : Interviewee provides the answer first, then supporting facts from the case, and finally risks and next steps

Setup (2-3 minutes)

Prompt : The interviewer may be giving you A LOT of information - don’t write down everything verbatim. Jot down facts and figures, the client name, and the objective(s). If you miss something or don’t remember what a number means, you can ask after your recap.

  • Prep: Have a friend read you several different case interview prompts and practice taking down notes. Create your own shorthand and learn how to recognize extraneous pieces of information

Recap : I always reference the client by name and start my recap with the objective(s) first, since this is the most important part of the case. The recap should be summarized, not verbatim, and you should be checking that the figures you wrote down are correct.

  • Prep: Practice summarizing your notes out loud instead of repeating the case verbatim. Time yourself to make sure it’s <1 minute.

Clarifying Questions : Very detailed questions should be saved for the case. Clarifying questions are meant to help you with your structure or alleviate any confusion. Keep these at 2-3 questions. I usually ask questions pertaining to:

  • Language/terminology - The interviewer won’t expect you to know the nuances of every industry or practice area. It is better you start off the case on the right footing by asking for clarifying definitions
  • Goals/objectives - I always ask if there are other goals the company has in mind and, if relevant, specific financial targets or timeframe. Sometimes, the objective given is vague, so I will ask the interviewer to be more specific.
  • Business model or geography - Very helpful for cases in niche industries; understanding geography can also prompt you to think about factors like labor cost or global competition
  • Scope - To save you time from considering every possibility, you can ask whether the company is leaning towards one option or excluding a set of options completely
  • Prep: Have a friend read you case prompts and then practice asking 2-3 clarifying questions on the fly. Try to think of them as you’re taking down notes and giving the recap. Are they helping you with your structuring or are you asking the first thing that pops into your head? Are they broad enough or overly detailed? Are there types of questions you should be asking but keep forgetting?

consulting case study calculation

Framework (4-5 minutes)

Structuring (<2 minutes) : Do not use the word “framework” during the interview. I ask if I could have time to “gather my thoughts” when I am structuring. In your structure, you should have at least three but no more than five “buckets.” These are areas that you want to explore in order to solve the case. In each bucket, there should be at least three sub-bullets. Make sure there is no overlap between the buckets.

  • Prep: Time yourself structuring your roadmaps. Be comfortable with recalling the different buckets you should be considering for each type of case and brainstorming sub-bullets for those buckets. It’s okay to go over two minutes when you first start, but as you get comfortable, make sure you are becoming more efficient. For example, as you become more familiar with the buckets, you don’t need to write down every example for the sub-bullets, they will become muscle memory as you recite them out loud. Review the suggested frameworks for the case and take note of whether there are vital topics you keep forgetting or whether there are unnecessary buckets you keep adding. There is no one “right” answer, but your roadmap should enable you to uncover the necessary information to make your recommendation.

Presenting: Introduce the high-level buckets first before diving into each one. You will want to “customize” your framework to the specific case you’re working on. This does not mean creating a custom framework for every single case. You can use the same topics for similar types of cases (but ensure that those topics are relevant - some cases sneakily rule out an entire topic to see if you are paying attention), but you need to make sure that you are using case-specific language and examples when you present. This shows that you are thinking about the specific problem, not just recycling a generic framework. After going through the structure, pause and ask if the interviewer has any questions. Then, give your hypothesis and state which bucket you want to start with by asking for data pertaining to that bucket and why you want it.

  • Prep: Present your structures out loud and note whether you are rambling or being case-specific in your language. If you find that your presentation is too long, consider cutting down on the examples or explanations. Be succinct and say enough to get your point across. Don’t just move on to the next case if your presentation falls short. Keep practicing until you feel satisfied and make mental notes for the next case.

consulting case study calculation

Interview “Questions” (10-20 minutes)

For each type of question, you are going to be doing the same things: answering the question, providing insights, conveying how it impacts your recommendation, and driving the case forward. Every time you have “answered” a question, you want to be thinking, “ What else do I need? What’s the logical path forward ?” The only way you can prepare for this is to run through entire cases! Remember, your framework is your friend. Refer back to it often if you don’t know where to go next.

Brainstorming : You will want to structure your ideas into MECE buckets. They can be fairly simple (financials vs. non-financials, external vs. internal, etc.). Similar to your framework, you will give a preview of the buckets first before going into the details of each and you will need to ensure that it is “custom” for your case. If a structure doesn’t naturally come to you, you can create a pseudo-structure by organizing how you will present your brainstorm. For example, you can state how many ideas you have from the onset or say that you will first go through the ideas first and then the associated risks.

This is a highly debated practice, but I always ask for a few seconds so I can think of a structure (they may say no). Don’t take more than 30 seconds because you can add to your buckets as you are presenting.

For non-technical brainstorms, be creative! For example, when interviewers asked about how to increase sales for a consumer-facing retail company, I would bring up TikTok campaigns and celebrity endorsements as a few ideas. Have fun with it!

Occasionally, interviewers will prod you with, “What else?” This does not always mean you didn’t give enough ideas. Sometimes it’s the opposite – they are looking to challenge you or see how you will react. Just roll with it - if you don’t have anything else, say so.

  • Prep: Practice brainstorming for different types of prompts. Collect a bank of general ideas and solutions that can be customized for use across industries. Try to think of as many ideas as you can (four to six at the very least) and exercise that creative muscle. To help you with structuring, have a list of “easy” MECE buckets that you can pull out on the fly.

Exhibits : First, give an overview of the exhibit. As an example, for graphs say what the axes represent, tie it back to the case, and give your interpretation of those axes. This gives the interviewer a chance to course-correct if you misinterpreted the exhibit. Give some insight, even if it is low-hanging fruit, and tie it back to the case. There are three levels of insights for both exhibits and math:

  • What the numbers say, patterns/trends (X is smaller than anticipated, Y is the largest driver)
  • What the client should do (enter the market, cancel plans, plan for launch)
  • What we should do next (reconsider something specific, research more data on X, move on to Y)

Oftentimes, exhibits will tie into a calculation. If you are given an exhibit with data that can be used to calculate more insightful information, tell the interviewer that you would like to make those calculations. The interviewer will lead you down that path regardless but it is more impressive if you call it out.

  • Prep: Run through different types of exhibits and see how many insights from each level you can pull out. Practice anticipating what type of data you need next in order to move ahead in the case or whether you can/should calculate anything from the data given. Don’t be too insightful though – you only have a limited amount of time to run through the case.

Math : Before you start calculating anything, it is critical for you to confirm what you are solving for and that the information you wrote down is correct. SUPER IMPORTANT – answer the question that is being asked !!  If the interviewer is asking for the incremental profit from a certain strategy, you don’t want to calculate the total profit from the strategy. Active listening is so important!

As you know by now, structure is everything. Again, I always ask for a few seconds to organize my thoughts (the worst thing they can say is no). Set up the problem before you start calculating. This allows you to identify whether there is data missing. Walk the interviewer through your method and ask for missing data. You may need to make your own assumptions or estimates – be sure you can justify them.

If your method is off, the interviewer will usually guide you back to the right path. This saves you from wasting time calculating the incorrect answer. Be sure to pay attention when the interviewer is trying to coach you.

As you are solving the problem, walk the interviewer through each calculation and use math shortcuts as much as possible. Again, if you make a math error, the interviewer can stop you before you go down the entire path. Save time by only calculating what is important for the case and understanding what you can skip.

  • Prep: Practice setting up the problem, walking the interviewer through your proposed method, and verbalizing the calculations out loud. On paper, make sure your calculations are being done neatly and not all over the place. Look for different math shortcuts and try them out. Not all of them will fit your style, but you might find new tricks. Track whether you are answering the right questions. Once again, active listening is critical to your candidacy. Once you have correctly solved the problem, make sure you are thinking about the, “So what?” Determine how that number impacts your recommendation and where you should go next.

consulting case study calculation

Synthesis and Recommendation (2-3 minutes)

Again, I always ask for a few seconds to collect your thoughts (<30 secs). If the “CEO is already in the elevator,” they may say no. Have a definitive stance – start with your recommendation and then provide two to three supporting facts using data from the case.

Address risks and next steps (i.e., what is the required analysis/gameplan – this is like real life where the firm is trying to sell additional projects). Your recommendation should be <2 minutes. Frankly, the interviewer has most likely made a decision on your candidacy. Don’t ramble and try to finish strong.

The hardest part of this is pulling out the supporting data in a succinct way. Throughout the case, you should be jotting down notes. I tend to circle what I believe to be relevant supporting data. When you present it, don’t be too specific or granular. You want your recommendation to be punchy.

  • Prep: Run through whole cases where you are tracking the relevant supporting data along the way. Time your recommendation and practice verbalizing the information concisely. Don’t forget the risks and next steps. I usually have a list of generic risks (e.g., competitor response, regulation, inaccurate projections) that I can “customize” on the off-chance I’m scrambling to think of some. Your next steps can be collecting additional data to support your recommendation or ways to address those risks.

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Final Thoughts

  • Your approach is more important than the solution – The interviewer is trying to understand how you think. Some cases have data that support recommendations in either direction. The key piece is that you are able to back your stance using the facts and data uncovered during the interview.
  • Deadends are okay – There will be times when you make multiple requests for data and the interviewer does not have it. That’s perfectly fine! You can’t read the interviewer’s mind and the case could go in so many directions. Just look back at your framework to see where else you can proceed.
  • Be coachable – It’s not the end of the world if your method is wrong or if you misinterpreted an exhibit. The interviewer wants to see that you are actively listening and can take feedback and improve. Don’t freak out! Stay calm! Listen to what the interviewer is trying to tell you.

This guide only scratches the surface of case interviews. The best way to prepare for case interviews is to get your reps in with entire cases. That way, you can identify your areas of weakness and be more precise with the drills. I can give you feedback and additional tips and tricks so that you are performing at your best on interview day. Book a free intro call with me on my Leland profile to discuss how we can personalize your case prep plan!

Preparing for consulting recruiting and/or case interviews? Here are some additional resources to help:

  • Top 3 Tactics to Ace Your Case Interview
  • A Comprehensive Guide to McKinsey & Co., Bain & Co., and Boston Consulting Group
  • From No Offers to Multiple Offers - How to Take Your Casing to the Next Level
  • How a Disneyland Churro Helped Me Land a Job at Bain (and 5 Pitfalls to Avoid in Market Sizing Problems)
  • Five Tips to Break Into Management Consulting

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Consulting & Case Interview Math Practice Guide

The truth is you do not need to be an expert mathematician to work as a consultant, still, you will need to do a lot of calculations when working in this field. 

The math concepts utilized in consulting are not more challenging than those studied from academic math. More exactly, it is different and attempting to solve problems the same way as in school will not be effective. 

This article will explain to you what makes math so important for aspiring consultants and provide you with some crucial math areas in which you need to be proficient in as well as how to best practice consulting math.

Table of Contents

Do you need math in consulting or case interviews?

Math is omnipresent in case interviews….

This industry is known for its complex business problems and challenging strategic decisions, which require a strong foundation in mathematics. Thus, mathematics is a fundamental skill that is essential for success in consulting case interviews .  

Consulting companies usually use case interviews to test candidates' quantitative skills and problem-solving abilities, which means that proficiency in math is a must-have skill for any aspiring consultant.

Candidates who are proficient in math have a significant advantage in the case interview process. They are better equipped to analyze data, create models, and make informed decisions based on quantitative analysis . This is because math skills enable candidates to think logically and analytically, which is crucial in the consulting industry.

In addition to helping candidates solve complex business problems, good math skills can also help them to solve the case more efficiently. By quickly identifying the key data points and using mathematical formulas to analyze them, interviewees can save time and leave more time for insightful ideas and recommendations.

… because it’s always there in real consulting work

Additionally to case interviews, the consulting industry as a whole also places a high value on mathematical ability. Without a strong foundation in math, consultants may struggle to work effectively in their daily duty.

Math skills are essential for performing data analysis and modeling, which are crucial aspects of the consulting job. Consulting firms rely heavily on data-driven insights to deliver value to clients, and math skills are necessary to analyze data, identify patterns, and draw meaningful conclusions that can help clients make informed decisions.

Secondly, to develop engaging talks and reports that successfully illustrate information and suggestions, solid arithmetic skills are also required. 

These abilities are essential since clients rely on consultants to provide them with actionable insights that can drive their business forward. By using mathematical formulas and models, consultants can present complex data in a clear and concise manner , making it easier for clients to understand and act upon.

Furthermore, math skills are crucial for financial analysis, which is another critical aspect of the consulting job. Consultants must be able to analyze financial data, create financial models, and make informed decisions based on quantitative analysis . This requires a strong foundation in math, including knowledge of statistics, probability, and financial mathematics.

7 Types of math you need in consulting

consulting case study calculation

Basic operations (add, subtract, multiply, divide)

Definition: Basic math refers to the fundamental arithmetic operations used in mathematics. It includes addition (+), subtraction (-), multiplication (x), and division (/), which are used to perform simple calculations and solve basic math problems.

These fundamental arithmetic operations are used in various calculations and are necessary for understanding more advanced math concepts. Basic math is used to calculate various metrics, ratios, and other complex work in consulting as well as case interviews. Without a strong foundation in basic math, it would be challenging to perform such calculations accurately and efficiently.

Suppose a consulting project requires calculating the total cost of producing 10,000 units of a product. The cost per unit is $50 for direct materials, $30 for direct labor, and $20 for overhead expenses. To calculate the total cost, we need to use addition and multiplication:

Total cost = (Direct materials cost per unit + Direct labor cost per unit + Overhead cost per unit) x Number of units

Total cost = ($50 + $30 + $20) x 10,000 = $1,000,000

Ratios and percentages

Definition: Ratio is a comparison of two or more quantities, while percentage is a ratio expressed as a fraction of 100. Ratios and percentages are used to express relationships between different variables and are commonly used in finance, statistics, and other fields.

Consultants frequently use ratios and percentages to analyze financial statements, assess market share, and evaluate operational performance. Additionally, they evaluate various scenarios and spot shifts over time using this kind of calculation.

Suppose a consulting project requires analyzing the profitability of a company. We need to calculate the gross profit margin, which is the ratio of gross profit to revenue expressed as a percentage. If the gross profit is $500,000 and the revenue is $1,000,000, we can calculate the gross profit margin as follows:

Gross profit margin = (Gross profit / Revenue) x 100%

Gross profit margin = ($500,000 / $1,000,000) x 100% = 50%

Management accounting formulas and principles

Definition: Accounting math is a set of mathematical principles and methods used in accounting to record, classify, and analyze financial data. It includes the calculation of various financial ratios, such as profit margin, return on investment, and debt-to-equity ratio, which are used to evaluate a company's financial health.

Accounting math involves the use of specific formulas and calculations to prepare financial statements, such as balance sheets, income statements, and cash flow statements. Consultants regularly have to use accounting math to interpret financial data, identify areas for improvement, and develop financial models.

Common accounting math formulas:

Balance Sheet Equation: Assets = Liabilities + Equity

Income Statement Equation: Revenue - Expenses = Net Income

Gross Margin Ratio = (Revenue - Cost of Goods Sold) / Revenue

Debt-to-Equity Ratio = Total Debt / Total Equity

Current Ratio = Current Assets / Current Liabilities

Suppose a consulting project requires analyzing the financial statements of a company. We need to calculate the current ratio, which is a measure of the company's liquidity. If the current assets are $1,000,000 and the current liabilities are $500,000, we can calculate the current ratio as follows:

Current ratio = Current assets / Current liabilities

Current ratio = $1,000,000 / $500,000 = 2

Basic finance formulas and principles

Definition: Finance math refers to the mathematical principles and methods used in finance to analyze and manage financial data. It includes the calculation of financial ratios, such as return on investment, net present value, and internal rate of return, which are used to evaluate investment opportunities and make financial decisions.

Finance math includes advanced financial modeling and analysis techniques, such as discounted cash flow analysis, net present value calculations, and internal rate of return analysis. Consultants will need to use finance math with purposes like evaluate investment opportunities, assess risk, and make strategic recommendations.

Present Value (PV) = Future Value / (1+interest rate)^number of period

Future Value (FV) = Present Value x (1+interest rate)^number of period

Net Present Value (NPV) = sum of all present values of cash inflows - sum of all present values of cash outflows

Internal Rate of Return (IRR) = the interest rate at which the NPV of an investment is zero

Return on Investment (ROI) = (Gain from Investment - Cost of Investment) / Cost of Investment

Suppose a consulting project requires evaluating investment opportunities. We need to calculate the net present value (NPV) of an investment, which is the difference between the present value of cash inflows and the present value of cash outflows. If the cash inflows for the first year are $50,000 and the cash inflows for the second year are $100,000, and the discount rate is 10%, we can calculate the NPV as follows:

NPV = Cash inflow year 1 / (1 + Discount rate)^1 + Cash inflow year 2 / (1 + Discount rate)^2

NPV = $50,000 / (1 + 10%)^1 + $100,000 / (1 + 10%)^2 = $126,456.83

Basic statistics and probabilities

Definition: Probability is the branch of mathematics that deals with the study of random events and their likelihood of occurring. It involves calculating the probability of different outcomes based on the available information and using this information to make predictions.

Probability is used in consulting to assess the likelihood of different outcomes and events, and to develop risk management strategies. Consultants use probability to analyze market trends, identify potential risks, make forecasts, and develop contingency plans.

Suppose a consulting project requires analyzing customer data to identify patterns. We need to calculate the probability of a customer making a purchase given that they have visited the company's website. If the number of website visitors is 10,000 and the number of customers who made a purchase is 500, we can calculate the probability as follows:

Probability of purchase given website visit = Number of customers who made a purchase / Number of website visitors

Probability of purchase given website visit = 500 / 10,000 = 5%

“Weighted” calculations

Definition: This is a method of calculating a value based on the weights assigned to different variables. It is commonly used in finance and economics to determine the overall performance of a portfolio, and in other fields to calculate averages of different sets of data.

A weighted average is used to calculate the average of a set of numbers, with each number being multiplied by a corresponding weight. This type of math is very useful for consultants since it helps them to analyze financial data, such as revenue growth or customer satisfaction, and to develop performance metrics.

Suppose a consulting project requires analyzing survey data. We need to calculate the overall satisfaction score for a product, which is based on ratings for different features. If the ratings for feature A, B, and C are 3, 4, and 5 respectively, and the weights for these features are 30%, 40%, and 30% respectively, we can calculate the overall satisfaction score as follows:

Overall satisfaction score = Rating for feature A x Weight for feature A + Rating for feature B x Weight for feature B + Rating for feature C x Weight for feature C

Overall satisfaction score = 3 x 0.3 + 4 x 0.4 + 5 x 0.3 = 3.0

Exhibits (chart, tables, diagrams)

Definition: An exhibit is a graphical representation (chart) of data that is used to present information in a clear and easily understandable format. It can be used to display trends, patterns, and relationships between different variables, making it a useful tool for visualizing complex data sets.

Consultants need to use charts and graphs to present complex data and analysis in a clear and concise manner. They use various types of charts, such as pie charts, bar charts, and line graphs, to convey important information to clients and stakeholders. They also help consultants to identify trends and patterns in data, making it easier to draw meaningful conclusions and make informed suggestions.

This part of mathematics is quite diversified since there are numerous types of charts, tables, and diagrams, thus I cannot provide examples for every situation. Learn more at: Six types of chart in case interview

Consulting mental math

Why is mental math in consulting important.

This may also be categorized as a type of mathematics, but I've decided to address it separately to emphasize the significance it is. In the consulting industry, quick math is essential. Although the resulting numbers don't have to be 100% accurate (usually the error margin will be around 5%) , you will have to give a quick result.

In many circumstances, there is not a sufficient amount of time to get out a calculator, indeed, they are not even permitted in tests and case interviews . Hence, Mental math is a crucial component of an interview that frequently gets noticed by interviewers when it helps candidates to solve the questions and show their mental agility. 

When you have become a consultant, mental calculation is even more important since it not only helps us save a ton of time but also builds credibility with people around . You wouldn't want to look sluggish and perplexed in front of your managers, clients or interviewers, would you?

How to do mental math for consulting?

For our Comprehensive Math Drills, we have developed a methodical approach to mental calculations with large numbers, consisting of two main steps: ESTIMATION and ADJUSTMENT. This method is used for multiplication, division, and percentage.

Step 1 - Estimation

  • Simplify the large numbers by  taking out the zeroes (e.g. 6,700,000 becomes 6.7 and 000000)
  • Round the resulting 1-to-2-digit numbers for easier calculations (e.g.: 6.7 becomes 7)

Step 2 - Adjustment

  • Perform simple calculations with the multiplicands
  • Adjust in the opposite direction of the previous rounding and put the zeroes back in

Step 3 - Percentages

  • To do percentages , multiply the original number with the numerator then divide by 100.

Detail example:

  • Multiplication: 1,234 x 5,678

Take out zeroes: 12.34 x 56.78 | 00 00

Round: 12 x 60 | 00 00

Calculate: 720 | 0 000

Adjust and add zeros: 7,200,000 (equal down-rounding and up-rounding roughly cancels each other out)

Accurate result: 7,006,652 | Error margin: 2.7%

  • Division 8,509 / 45

Take out zeroes: 85 / 4.5 | 00 / 0

Round: 90 / 4.5 | 00 / 0

Calculate: 20 | 0

Adjust and add zeros: 190 (up-rounding means downward adjustment)

Accurate result: 189.09 | Error margin: 0.48%

  • Percentage 70% of 15,940

Convert %: 0.7 x 15,940

Take out zeroes: 7 x 15.9 | One 0 in, three 0 out

Rounding: 7 x 16 | One 0 in, three 0 out

Calculate: 112 | One 0 in, three 0 out

Add zeros: 11,200

Adjust : 11,150 (up-rounding means downward adjustment)

Accurate result: 11,158 | Error margin: 0.07%

For percentage calculations, it is even easier with the “ Zeroes management ” . We know that the final answer will have roughly the same number of digits as the original 15,940, something like 1x,xxx or x,xxx. So when having 112 after step “Calculate”, we know the final answer would be close to 11,200.

Mental Math Tips:

  • Write down numbers : it’s always a good idea to have a visual of the numbers themselves on paper. This makes it 100 times easier,  especially with “zeroes management” work.
  • Sanity check: always take a very brief moment to ask yourself “is this result logical?”; if 70% of 15,940 equals 111,500, perhaps something is wrong with your “zeroes management”. Sometimes you can compare the outcome with another obvious data
  • Shortcut percentages: convert percentages into easy, common calculations (e.g.: 33%, 25%, 20% into /3, /4, /5…) if possible. In fact, know as many of these shortcuts as you can.
  • It is better to be long than to be wrong: If your mental math is not good and cannot calculate quickly, do not hesitate to ask for a little more time to get the most accurate answer.

Consulting math practice

Step 1: learn about yourself.

The first step to acing consulting math is to understand yourself, your strengths, your weaknesses and your needs. Assess your current skill level and identify areas where you need to improve . This can be done by reviewing your previous academic performance, past work experiences, and feedback from others.

One of the best ways to learn more about the consulting industry and the type of math skills required is to network with those who have experience in this field. They can provide valuable advice and insights on what to expect during tests/interviews and which math skills are most important. 

This is an extremely important step, but it might be challenging to carry out since many people do not know/have contact with any consultants, former consultants and interviewers. If there are a few people in your network, that's fantastic; if not, you can use our Coaching services to get the most reliable information from current consultants.

Step 2: Developing an actionable plan 

Once you have a clear understanding of yourself, you now need to establish a clear, actionable strategy to improve your consulting math skills . This plan should include a list of resources and activities that will help you promote self-study and focus on the areas that need the most improvement.

There are many resources available for consulting math practice , including online courses, textbooks, and practice mental exercise. You may also want to consider hiring a tutor or attending a community to receive personalized guidance and feedback.

When developing your plan, it is important to set realistic goals and establish a timeline for achieving them. This will help you stay motivated and track your progress along the way.

Step 3: Implement the plan

Now that you have a plan in place, it's time to implement it. Set aside dedicated time each day or week to practice your consulting math skills . Consistency is key, so make sure you stick to your schedule and do not skip any practice sessions.

When practicing, it is important to focus on understanding the underlying concepts rather than simply memorizing formulas and equations. Work through practice problems step-by-step and identify where you might be making mistakes. 

Moreover, reviewing your work and seeking feedback from others can help you improve your approach and increase your accuracy.

Step 4: Adjust the plan to best suit your capacity

Finally, It is crucial to modify your strategy as necessary to accommodate your capabilities. If you find that you are struggling with a particular concept or area, don't be afraid to pivot and adjust your plan accordingly. Consider seeking additional resources or seeking guidance from others who have experience.

At the same time, do NOT get too caught up in perfecting every aspect of consulting math is also matter. Recognize your strengths and weaknesses and focus on improving in areas where you can make the most progress. 

Remember that the goal is not to be perfect but to demonstrate your ability to approach and solve complex problems in a logical and efficient manner.

Common math mistakes in consulting 

Messing up formulas.

The inability to apply the formula errors or mess up with numbers/signs is a common mistake made by candidates. Anyone may make this error because of both internal factors like mathematical confusion and external factors like time pressure.

To avoid this issue, you must first be cautious throughout the procedure, go step-by-step, and carefully examine the data and signs . If you need extra time, kindly request it, keep in mind that the important thing is getting the proper outcome.  

Secondly, practice using different formulas to solve various problems before the interview. Ensure that you have a clear understanding of when and how to apply each formula.

Excess or missing zeroes

Another common math mistake is losing units in calculations. When performing calculations, you must keep track of units to ensure that your answer is meaningful and relevant to the context of the problem. Losing units can make your answer meaningless and confusing, which could lead to wrong conclusions.

In order to avoid making this error, it's essential to label each step of your calculation and remember to carry the units as you work with them . Keeping your calculations well-organized will prevent you from losing track of the units. 

Another tip is try to reduce the unit of each metric as much as possible by assigning it to a term. For example, you can write “42,000,000” to “42M”. This will both ease your calculations and avoid confusion, but remember to add the units back to the final result 

Missing the bigger picture

The math done during a consulting case interview serves as a tool, not an end in and of itself. It is crucial to remember that calculations are part of a more significant business problem that you have to solve . 

Many candidates get wrapped up in calculations, arrive at the correct final number, but forget why they were doing the math and the real purpose of the number they have just found out.

To prevent this mistake, remember the significance of the figures you are calculating in the context of your particular business case. One tactic to use is to write the question asked at the top of your sheet before deep diving into your math. 

As you go through your calculation and as you prepare to present your solution, keep reminding yourself the question you were originally asked and ask yourself if the result you got from your calculation is actually answering it. Then when you explain your answer, do so in a way that clearly shows you understand what your final number means.

Scoring in the McKinsey PSG/Digital Assessment

The scoring mechanism in the McKinsey Digital Assessment

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Mental math is a must-have skill for a consultant, not only for screening tests and case interviews but also for real consulting work.

Six types of charts in case interview are: Bar/Column chart, Line chart, Percentage chart, Mekko chart, Scatter plot chart, Waterfall chart.

Business knowledge is not a mandatory condition to become a consultant. Nevertheless, it still has specific obligations and advantages for consultants.

Career in Consulting

Case Interview Prep

Case interview prep: The definitive guide

This is the complete guide to boosting your case interview prep in 2023.

In this in-depth guide, you’ll learn:

  • How to effectively prepare for case interviews
  • How to turn your case interviews into job offers
  • How to avoid the mistakes that lead to rejection
  • And lots more

So, if you want to secure offers at McKinsey, BCG, or Bain & Company, this guide is for you.

Let’s dive right in.

Table of Contents

Case interview fundamentals.

In this section, you’ll get a handle on the fundamentals.

Whether you are new to case interviews or want to ensure you are on the right track, you’ll love this section.

Then, in later sections, we’ll cover advanced tips, techniques, and strategies to ace your management consulting interviews.

But first, let’s cover the basics of case interview prep.

The hiring process in consulting

What is a case interview?

A case interview is a job interview technique.

A case interview – or case study – is a job interview technique to assess a candidate’s potential to become a successful consultant.

To do so, management consulting firms ask candidates to solve real-life problems their clients face .

Hence, this perfectly simulates the job you must do as a Consultant.

For instance, here are two sample case questions from Bain & Company’s website .

Sample case questions (Bain & Company)

And here are more examples from the McKinsey & Company website .

McKinsey case interview examples

A case interview is a problem-solving test

To solve these real-life problems, you must go through a certain number of steps, such as identifying the key drivers of the problem, asking the right questions to walk your way through the case, analyzing data, and presenting a solution to the problem.

But don’t worry: I’ll detail these steps later in this guide.

The problems you have to solve in a case interview are diverse both in terms of industry (Hospitality, Transportation, Chemical, Banking, Oil & Gas, Private Equity, etc.) and business situation (improving sales or profits, decreasing costs, rethinking an organization, acquiring a company, etc.)

Diversity of case questions in consulting

And they are usually taken from real-life projects done by the interviewers .

Another important rule in a case interview:

There is no right answer (but plenty of wrong answers).

Hence, what’s important for your interviews is your reasoning.

And this means they are more interested in your thinking process than a solution for the problem.

Here is an example from Bain’s website:

What is NOT a case interview?

I’ve been coaching candidates for over a decade.

And I’ve seen this misunderstanding too many times:

A case interview is NOT an exam .

Case interviewers are NOT testing your KNOWLEDGE or your memory.

They are testing your COGNITIVE SKILLS .

Which means:

Your ability to effectively use and adapt your knowledge to solve complex problems.

That’s why memorizing frameworks or formulas is useless… and often counterproductive.

There is no shortcut to ace a case interview.

Instead, you must develop your problem-solving and communication skills.

Remember this:

A case interview should be a conversation between 2 consultants solving a business problem.

This is far from being a student answering exam questions on a piece of paper alone.

Who uses case interviews and why?

All top management consulting firms use case interviews to assess a candidate’s problem-solving skills.

So, why do consulting firms use case interviews in their interview process?

Why consulting firms use case interviews

You must understand this:

Management Consultants consider themselves professional problem solvers.

And during the case interview process, they want to see if you are one of them .

They want to see if you think and speak like them.

Professional problem-solvers

Here is a non-exhaustive list of consulting firms using case interviews in their interview process:

McKinsey & Company

Boston Consulting Group

Bain & Company

Oliver Wyman

Roland Berger


Monitor Deloitte

Note: This list is by no means exhaustive. Lots – if not all – boutique consulting firms use case interviews as well as part of their interview process.

The formats of case interviews differ from one firm to another.

And that’s what we are going to discuss in the next paragraph.

What are the different types of case interview formats?

Now, it’s time to discuss the two formats of case interviews:

Candidate-led case interviews

Interviewer-led case interviews

More specifically, you’ll learn what are the differences between a candidate-led and an interviewer-led case interview.

Also, you’ll learn what are the implications of these formats for your case interview preparation.

The first case interview format: Candidate-led case interviews

Most firms use a candidate-led format.

What does candidate-led mean?

In candidate-led interviews, the candidate is expected to drive the case from start to finish.

This means they are responsible for structuring the problem, asking the right questions, and leading the discussion towards a solution.

In other words, the candidate is in the driver’s seat.

They must proactively identify issues, prioritize them, and decide on the next steps.

Therefore, there’s often more room for creativity and exploration.

If the candidate decides to explore a particular area of the case in-depth, they have the freedom to do so.

The second case interview format: Interviewer-led case interviews

McKinsey uses interviewer-led interviews (so do – sometimes – Oliver Wyman and Strategy&).

In interviewer-led cases, the interviewers are more active in guiding the discussion.

After the candidates present the key topics to be analyzed to solve the business problem, the interviewers lead the direction on where to start diving into the analysis. 

While the candidate must still showcase their problem-solving skills, the interviewer largely determines the case’s direction.

The interviewer might direct the candidate to specific areas they want to test, making the case feel more structured and segmented.

Candidate-led vs. Interviewer-led case interviews

The implications of the case interview format for your case interview prep

For Candidate-led Interviews, you need to be comfortable with taking the lead.

This means you should practice deciding which areas to probe further and which to deprioritize.

And I’ve created a free consulting case interview preparation course to show you how to do it:

Get 4 Complete Case Interview Courses For Free

consulting case study calculation

You need 4 skills to be successful in all case interviews: Case Structuring, Case Leadership, Case Analytics, and Communication. Join this free training and learn how to ace ANY case questions.

For Interviewer-led Interviews, you must be quick, adapt to new information, and change your approach as needed.

Therefore, active listening is crucial to ensure that you’re addressing the issues raised.

However, while there are distinct differences between candidate-led and interviewer-led case interviews, the core skills being tested are consistent across both formats .

What to expect in case interviews?

Most candidates hear “case interviews” for the first time when they decide to apply for consulting jobs.

And for most candidates, this is the biggest obstacle between them and their dream job.

So, in this section, we will go through the 5 steps of a case interview.

All interviewers from McKinsey, BCG, Bain, or other top consulting firms expect you to follow these 5 steps.

Note : The techniques and strategies to ace these steps will be discussed in the section “How to ace your case interviews.” later in this guide.

The 5-step problem resolution process

Open the case

A case interview starts with the interviewer sharing the case prompt with you.

In the case prompt?

The interviewer shares a client’s situation and the problem they are trying to solve.

While the interviewer speaks, you must take notes.

You must write down all the critical information and keywords of the case prompt on a piece of paper.

Don’t worry:

This guide will address how to recognize the “critical information and keywords” of a case prompt.

And after the interviewer finishes sharing the case question, it’s your turn to speak…

Clarify the problem

You can assume that all the case prompts will be ambiguous.

Some critical information will be missing.

Or some keywords will be ambiguous.

And it’s your first job to remove any ambiguity.

An example?

Imagine this case prompt:

Your client manufactures cars. They have been experiencing declining sales and are asking for your help .

In the above case prompt, you should clarify what types of cars they manufacture.

A mass-market model like a Toyota Corolla?

or a luxury model like a Ferrari Spider 488?

The case’s direction will be very different whether we discuss one model or another.


You must ask clarifying questions to understand precisely the situation and goal.

Also, if you don’t understand a word, ask your interviewer to define it.

Develop a tailored framework

For most candidates, this is the scariest part.

During this step?

You must develop a mutually exclusive and collectively exhaustive (known by its acronym: MECE ) issue tree.

An issue tree can also be called a case interview framework (or case interview structure ).

Now, let’s address the following questions:

What is a case interview framework?

Why is this important?

What are the characteristics of a good case interview framework?

First, let’s define what a case interview framework is.

A case interview framework is your plan to solve the problem.

In other words:

This is your roadmap to move from the problem to the solution.

And during the case, you’ll walk your interviewer through this roadmap.

This roadmap must include all the factors that influence the behavior of the problem.

For instance: volume and price influence the behavior of sales.

And these factors must be organized by following certain principles (the infamous MECE principle ).

All these factors must be organized in a mutually exclusive and collectively exhaustive way to ensure that there is no gap (no important factor is missing) and no overlap (no factor is counted twice).

Now, what makes a great case interview framework?

Watch this video detailing the three characteristics of a superior case interview framework:

MECE (mutually exclusive and collectively exhaustive)


Solve the problem

After you’ve presented your roadmap, you must ask relevant and insightful questions to the interviewer.

Get data and information to solve the case.

Your interviewer can provide you with data in three forms:

Then your job is to interpret these data.

You must turn these data into business insights.

Note: an insight is the meaning of the data in the context of the problem (more detail on that later).

This is called the “so-what” in top consulting firms.

At this stage, your interviewers mainly test your analytical skills and business judgment.

For instance, they ask themselves:

Can you connect the dots between different sets of data?

And can you derive conclusions from these sets of data?

Besides, interviewers also test your quantitative skills.

They might ask you to perform quick mental calculations (also known as case interview math).

And when you have formed many conclusions from the data analysis, you can derive a recommendation.

Now, it’s time to move to the next step.

Close the case with a solid recommendation

The final step consists of delivering your recommendation to your client.

This is when you tell your client what to do, why they should do it, and why it’s important.

This is when you shift from an “analysis mode” to a “presentation mode.”

You are now talking to your client’s CEO.

To deliver your recommendation, you must follow the top-down communication principles popularized by Barbara Minto in her book “ The Pyramid Principle ” (a must-read if you want to have a successful business career).

Hence, you must:

Start with your recommendation (or your answer to the client’s question).

Provide supporting arguments, usually taken from the analyses you performed during the case.

Discuss the next steps your client must take.

At this stage, your interviewers mainly test your communication skills.

But they also test your business judgment.

For instance, by asking themselves if your recommendation is actionable or not.

And… that’s it!

You are now done with your case interview.

Or at least you have an overview of the different steps of a case interview.

Now, you can watch this video where I present the 5 steps in detail:

What do case interviewers look for?

In this section, you will understand how you’ll be evaluated .

There is no secret: You must understand the rules of the game to have a chance to win.

And most consultancies – if not all – use the same criteria to assess a candidate’s case interview performance.

But let’s be clear:

In a competitive sector like Consulting, you must be in the top 1% of candidates across all these criteria to land an offer .

So, if you’ve ever wondered what it takes to be in the top 1%, you’ll learn a lot from this section.

Hard skills: the 4Cs and business acumen

During the screening phase, HR professionals check your resume and cover letter to establish if you have the potential to be a good candidate.

And during the case interview process, Consultants test this potential to establish if you’ll become a best-in-class consultant.

Consultants want to see if you have the skill set to become this best-in-class consultant.

The 4Cs of case interviews

Case structuring

Interviewers assess your ability to identify all the relevant components of a problem, to organize these components in a MECE way , and to explain clearly how each of these components helps solve the overall problem.

Case leadership

Interviewers assess your ability to prioritize the issues to analyze. You must demonstrate your 80/20 thinking (your ability to identify the 20% of issues that will solve 80% of the problem).

Case analytics

Interviewers assess your ability to transform data into insights. If data is the “what,” then the insight should be the “so what.” In other words, your ability to say what the implications of data are.

Communication skills

Interviewers assess your ability to communicate your ideas clearly and keep the interviewer engaged and aligned with your thinking process during the entire case discussion.

Also, clear and concise communication shows your interviewers that you are client-ready.

Business acumen

Business acumen – or business sense skills- is the top 1% factor.

This is how:

An issue tree is more tailored to the problem to solve

Only the most impactful issues are addressed

The interpretations of data are more insightful

In short, this is your ability to understand what moves the needle in problem solving.

Case interview prep: The top 1% factor

Soft skills: personal characteristics

Besides the above hard skills, consulting firms check if you have the personal characteristics demonstrated by the best-in-class consultants.


Feedback is a significant part of the culture in consulting.

Consultants receive formal feedback every 3 months (after each project) and informal feedback throughout the project.

So, interviewers check how you react to feedback.

Do you listen well, understand, and implement feedback?

Or do you defend your opinion at all costs?

And be careful: lack of coachability is a red flag for many interviewers.

Are you excited about working on a new project (in a new industry) every 3 months?

If the answer is yes, consulting can be a good career option for you.

A curious mind (or “growth mindset”) is an important characteristic of being a successful consultant.

Therefore, your answers in fit interviews or your attitude during case interviews should showcase your burning desire to learn new things.

Case interview prep: Intellectual curiosity

Comfort with ambiguity

In management consulting, you’ll have to solve tough business problems while having incomplete information.

So, your case interviewers test how you deal with ambiguity.

And a consulting case interview is full of ambiguities!

Check this article to learn how to clarify a case prompt .

Confidence & maturity

Consulting is a client-facing job.

And top consulting firm clients – corporations or public organizations – pay tons of money for their services.

So, interviewers ask themselves, “Do I feel comfortable putting this person in front of my client?”.

Important note : Since I sometimes get the question, you’ll have your chance regardless of your personality (introvert or extrovert).

Case interview examples from different consulting firms

I will share two in-depth case interview examples with you in this chapter.

That way, you can see the strategies and techniques from this guide in action.

Specifically, we will discuss the two types of case interviews used by top consulting firms:

Business cases

Market sizing questions

And for each type of case interview, I’ll share examples with you.

Note: per my experience, top consulting firms do not use brainteaser questions .

Therefore, this guide will not discuss this type of question.

However, I encourage you to check if your target company uses such questions (other consulting firms might still use brainteasers in their hiring process).

Business problem examples

Business cases are the most common questions you can have in a case interview.

You are asked to solve a business problem for a fictional client.

Similar to real consulting engagements, business cases are typically organized by industry and functional category.

case interview matrix

The industries you might encounter in a case interview are:


Automotive & Mobility,

Consumer Goods,


Energy (Oil, Gas, Power),

Financial Services,

Healthcare & Life Science,



Metals and Mining,

Paper and Packaging,


Private Equity,

Public and Social Sector,

Real Estate,


Technology & Telecommunication,


Travel and Tourism

Utilities & renewables.

Bain - Industries served

The functions you might encounter in a case interview are:

Corporate Finance,

Digital & Technology,


Mergers and Acquisitions,


People and Organizational Performance,

Recovery and Transformation,

Risk and Resilience,

Sales & Marketing,

ESG & Sustainability.

Bain - consulting services

The following topics, which are not MECE , could be covered in case interviews depending on the function and the industry:

Growth strategies

Market entry

Cost optimization

Organization optimization

Product launch

Profitability case interview

Here is a first McKinsey case interview example:

McKinsey case interview example (DICOSA)

Source: https://www.mckinsey.com/careers/interviewing/diconsa

Another example?

Here is another McKinsey case interview example:

McKinsey case interview example (TALBOT TRUCKS)

Source: https://www.mckinsey.com/careers/interviewing/talbot-trucks

And here is a BCG case interview example:

BCG case interview example (Healthcare)

Source: https://careers.bcg.com/case-interview-preparation .

Finally, over 250 case interview examples (with answers) are found on this page .

280 free case interview examples

Sample market sizing questions

A market sizing question is a case interview where you have to estimate the size of something with no (or little) data available .

Market sizing questions can be embedded in business cases or can be asked as standalone questions.

For instance, here are some sample market sizing questions:

How many coffee cups does Starbucks sell in a year?

What volumes of beer are sold during an LA Lakers basketball game?

How many iPhones are currently being used in China?

What is the monthly profit of an average hair salon in the UK?

Market sizing questions are a very popular type of case interview at top consulting firms.

So let me be clear:

You can NOT land an offer at McKinsey, BCG, or Bain if you don’t know how to solve market sizing questions.

That’s why I’ve written a comprehensive step-by-step guide on market sizing questions here .

In this guide, you’ll learn my best strategies to solve the 3 types of market sizing questions .

Also, you’ll find plenty of examples to see how these strategies work.

Market Sizing Questions

Old vs. New cases (2021 - present)

For the past few years, case interviews have changed.

Until a few years ago, case questions looked like this:

Declining sales

Declining profits

In short, the types of questions you can find in books like “ case in point” or “ case interview secrets.”

Less than 40% of case interviews are questions from the above list.

The other 60%?

Non-traditional case questions.

For instance, McKinsey recently asked this question:

Your client is a fictional country. They want to develop a plan to fight climate change. How would you help them with this question?

McKinsey - example of a non traditional case question

So, why have consulting firms decided to use this new type of question?

Because the goal of case interviews is to understand how you think.

And more precisely:

How you think outside your comfort zone.

Have you learned all the well-known business frameworks?

👉 They test your ability to solve business problems where these frameworks are irrelevant.

Do you have an Engineering degree?

👉 They will give you a case involving lots of business concepts.

Don’t have quantitative experience?

👉 They will give you a case with lots of math, charts, and numbers.

And it makes a lot of sense.

Because it mimics the day-to-day job of a consultant:

Consultants are constantly outside their comfort zone.

And they are constantly exposed to new topics.

Now, the implications for you are very important.

You can’t only rely on well-known frameworks.

Instead: you must learn how to build your own tailored frameworks.

You must learn how to think with First Principles and top-down logic.

You must learn how to organize your ideas in a MECE way .

Even for non-traditional case questions.

And I’ve created 4 free consulting case courses to learn just that:

How to ace your case interviews

In this section, I’ll show you how to turn your case interviews into offers.

In fact, the strategies in this section have helped over 350 candidates land job offers at McKinsey, BCG, Bain, or any boutique consulting firms.

And the strategies I share here can be used in all types of cases: market entry, profitability case interview, M&A, etc.

Let’s start with how to open a case like a pro!

Acing the opening: remove ambiguities

There is a lot of misleading information online about how to open a case:

Paraphrase the case prompt (aka repeat information your interviewers already know).

Ask a maximum of 3 clarifying questions.

End by asking if there is any other objective you should know.

But there is a better way to open a case:

Add business colors.

Take the lead.

Ask clarifying questions (as much as necessary).

Do a smart recap.

Here’s the truth:

How you open a case sets the tone for the entire case.

Start poorly, and your interviewer won’t guide you much during the case.

On the other hand:

Give a strong first impression, and your interviewer will see you as one of them from the first seconds of the case.

And that can be a game changer in your performance and chances to land an offer.

Therefore, this must-read guide will show you how to start your case interview correctly.

Acing the case structuring: create the perfect issue trees

We discussed this before:

An issue tree is the strategic framework that guides your analyses and helps you answer the client’s question effectively.

Before we dive into the nitty-gritty, let’s revisit the three essential characteristics of a robust case structure:

1. MECE (Mutually Exclusive, Collectively Exhaustive): Your structure should cover all possible areas without any overlaps.

2. Logic-Driven: The structure should follow a logical flow, making the logical connection between the different areas and the problem clear.

3. Tailored: Your framework should be customized to the specific problem at hand, not a one-size-fits-all template.

It shows that you can think strategically, organize your thoughts, and approach problems methodically—all essential skills in consulting.

Take Your Case Structuring Skills to the Next Level

Ready to master the art of case structuring?

Sign up for our free 4-hour video case interview training course .

This comprehensive course will walk you through the intricacies of developing a winning case structure, complete with real-world examples and actionable tips.

Acing quantitative questions: conquering numbers!

The mere mention of case interview math questions can send shivers down the spines of candidates with weaker quantitative backgrounds.

But hold on!

These questions aren’t just about doing quick mental calculations.

In fact, interviewers are looking for three crucial elements:

Structured Approach : Can you systematically break down the problem?

Numerical Comfort : Are you at ease with numbers and capable of swift mental calculations?

Business Sense : Can you interpret the results in a way that makes business sense for the client?

In the realm of case interviews, math questions often serve to calculate data that fills in the gaps in a given problem.

For example, you might be tasked with:

Market Sizing : For instance, estimating the potential size of a market.

Financial Metrics : For instance, calculating performance indicators like Payback Period or ROI.

Solution Impact : For instance, assessing the potential cost savings or productivity gains from a particular initiative.

The Truth About Mental Math

The world of mental calculations in case interviews is fraught with myths.

Let’s debunk some:

Reality : Calculators are a no-go. You’re on your own.

Reality : A significant math mistake is often a one-way ticket to rejection.

Reality : While some may tell you it’s okay to round numbers, most interviewers would disagree.

The rules can vary depending on who’s sitting across the table from you, so always be prepared for the strictest guidelines.

Follow This 4-Step Approach to Ace Quantitative Questions

Step 1: Define an Arithmetic Equation

The first step is to translate the business problem into an arithmetic equation.

This is where your structured approach comes into play.

Step 2: Do the Math

The data needed to solve the equation are usually provided by the interviewer.

If not, don’t hesitate to ask.

Occasionally, you’ll need to make educated estimates.

When calculating, remember: accuracy trumps speed.

Step 2bis: Do a Sanity Check

Before you share your answer, do a quick sanity check.

Does the result make sense in the context of the problem?

If something feels off, revisit your calculations.

Step 3: Share Your Insights

This is where your business sense shines.

Interpret the numbers and discuss their implications for the client’s situation.

Step 4: Lead the Case

Based on your calculations and insights, guide the conversation toward actionable recommendations.

Here is an example:

Interviewer : “How many units does a car manufacturer need to sell to break even?”

Candidate : “To find the breakeven volume, we can use the equation: Fixed Costs / (Selling Price – Variable Costs). Given that the fixed costs are $10 million, the selling price per unit is $20,000, and the variable costs are $15,000, the breakeven volume would be 1,000 units.”

How to Practice Math Questions

To sharpen Your Skills:

Mock GMAT Tests : These tests are excellent for practicing a wide range of quantitative problems.

Case Interviews : Simulate the real experience by going through case interviews that include math questions.

But don’t limit yourself to traditional methods.

Various online platforms and apps are designed to help you practice mental calculations and case-specific math problems.

By mastering case interview math, you’re not just showcasing your ability to crunch numbers.

You’re proving that you can think critically, make data-driven decisions, and lead a case to its logical conclusion.

Acing chart interpretation questions

Knowing how to interpret charts should be part of your consulting toolbox.

And to crack the case, you’ll have to analyze data presented in the form of charts or data tables.

While it looks straightforward, the challenges are numerous:

The quantity of data presented can be huge, and your time to analyze these data is limited. And some firms – like BCG – like to present charts with lots of irrelevant data…

Charts can come in many forms: bar charts, line charts, pie charts, scatter plots, etc. You must know how to decode each type of chart.

The game you’re playing here is not to read the data correctly but to turn these data into insights (the “so-what”). Your business judgment will make the difference here.

You sometimes need to use data presented 5 minutes ago in another chart to complete the actual analysis.

Understand the different types of charts

A chart is an immensely powerful way of presenting numerical data. All the information is summarised in one go in a way that the eye can readily absorb.

Trends, proportions, and other relationships are revealed at a glance.

If you are unfamiliar with the different types of charts, I recommend reading the book: “Say It with Charts” by Gene Zelazny.

This book is a masterpiece when it comes to explaining why a type of chart is used to convey a certain type of message.

But if you don’t have time to read these books, remember just this:

Each chart has one (and one only) objective.

The main objective a chart can have is:

Identifying a trend (line charts or column charts)

Showing the relative contribution of different categories to a whole (pie charts)

Comparing different items against a metric (bar charts)

Identifying the correlation between 2 data sets (scatter plots)

So, the next time you see a chart, ask yourself:

What’s the chart type (pie chart, line chart, etc.)

What’s the objective of this chart (showing a trend, comparing items, etc.)

What do data say?

Let’s discuss how to master the exhibit reading.

Follow this 5-step approach to ace chart interpretation questions

Here is a 5-step approach to ensure you’ll never miss any insightful information from a chart:

Step 1: Understand the data represented.

Take the time to read the information about the chart (titles, labels, X-axis, Y-axis, units, footnotes, etc.)

And clarify any word or information that is not clear. Asking questions is part of the consultant’s job!

Per my experience, 80% of the chart interpretation mistakes come from misunderstanding the data represented.

Step 2: Ask for time to structure your thoughts.

It’s okay to ask for 30 seconds to 1 minute to structure your thoughts.

Don’t be afraid of the silence… your interviewer prefers to have a structured and insightful conversation rather than rambling.

Step 3: Define your goal (top-down vs. bottom-up approach)

This is the biggest mistake I see:

Candidates use a bottom-up approach instead of a top-down approach.

The difference?

With a bottom-up approach, candidates jump into the data and hope to find something insightful.

In other words, they start their analysis without a plan.

Candidates with a top-down approach start with a plan before jumping into the data presented in the chart.

Their plan?

They start with the issue they were analyzing.

And list the data they need to solve this issue.

Finally, search for these data in the chart presented.

With this top-down approach, you will be able to sort the relevant data from the irrelevant information easily.

Step 4: Communicate your key insights and implications.

During this step, you tell your interviewer what the data means regarding the client’s problem.

Do NOT say obvious observations!

“This data is going down…”

“The value of <any metric> has been stable for the past 2 years…”

These are not insights… but obvious observations.

Your job is to interpret the data.

Here are some questions to ask yourself:

What do these data mean for the client? 👉 Insights

What does the client should do? 👉 Implications

  Step 5: Lead the case.

Regardless of the format of the case interview (interviewer-led or interviewee-led), I recommend proactively saying what the next steps are.

Discuss, based on your findings, what you want to discuss next.

How to practice chart interpretation questions?

First, you can practice with GMAT tests.

Here are some examples .

Besides, visit websites full of charts like The Economist, The Wall Street Journal, etc.

Find charts, draw conclusions from these charts, and read the article to check if your conclusions make sense.

Also, practice with the case examples you can find in these case books .

Acing market sizing questions

Do you struggle with market sizing questions?

This can include: How to start the case? Which clarifying questions to ask? How to organize my thoughts and build an issue tree? Which assumptions to make? Do I have to check if my estimate makes sense? If yes, how?

Answering a market sizing question can be very SIMPLE.

Actually, it is very simple: there is a PROVEN FORMULA for solving market sizing questions.

This PROVEN FORMULA is like a comprehensive guide: if you follow each step, you’ll QUICKLY answer ANY market sizing questions SUCCESSFULLY.

In this guide, I’ll reveal my PROVEN FORMULA to answer market sizing questions and show how to use it with two full examples (with answers).

You can find this comprehensive guide here .

Acing the closing: The Art of giving a Winning Recommendation to the CEO

You’ve analyzed the data, solved complex problems, and navigated through the case interview.

Now, it’s time to wrap it up with a compelling recommendation for the client’s CEO.

Your closing remarks can make or break your chances of landing that coveted consulting role.

Here’s how to avoid common mistakes and structure an impactful recommendation.

Mistake #1 When Closing the Case: Repeating the Analyses You've Done

You’re now speaking to the CEO, not a fellow analyst.

The CEO doesn’t care about the number of Excel models you’ve built or interviews you’ve conducted.

They want a clear, actionable solution to their problem.

So, skip the methodology and get straight to the point.

Mistake #2 When Closing the Case: Not Being Assertive

This is not the time for ambiguity or hedging.

CEOs seek decisive, confident recommendations.

If you’re not assertive in your closing, you risk losing the CEO’s trust and, consequently, the case.

Mistake #3 When Closing the Case: Not Having a Clear Recommendation

If the CEO is left wondering, “Okay, but what should I do?” after your presentation, that’s a red flag.

Your recommendation must be crystal clear, leaving no room for interpretation or doubt.

How to Close the Case: The Structure of an Amazing Recommendation

To craft a recommendation that hits the mark, follow this structure:

Step 1: Initial Question Asked

Begin with a one-sentence summary of the question you’re answering.

For example, “You asked us to determine whether you should launch this new shampoo?”

Step 2: Your Recommendation

Provide a straightforward answer to the initial question.

For instance, “You should launch this new shampoo.”

Step 3: The Supporting Arguments

List all the logical reasons that back your recommendation.

For example, “This new shampoo will add $10 million in profits and doesn’t require significant investment in R&D or new production equipment.”

Step 4 (Optional): The Next Steps

If applicable, outline the immediate actions the CEO should take to implement your recommendation.

The Role of Risk in Your Recommendation

While some coaches advise discussing risks separately, I believe risks should be integrated into your supporting arguments.

If you can’t mitigate the risks, your recommendation loses its value.

The Timeframe for Impact

Lastly, ensure your recommendation can deliver impact within the CEO’s tenure—typically less than five years.

A great recommendation is not just insightful but also timely.

Where to start: A comprehensive case interview preparation plan

Are you feeling overwhelmed by the thought of case interviews?

You’re not alone.

With all the resources available online, knowing what’s relevant and how to separate the wheat from the chaff is difficult.

But with the right preparation plan, you can make it!

This 3-step plan takes you from discovery to mastery, ensuring you’re well-prepared for your case interviews:

Step #1: Discovery

Step #2: Practice

Step #3: Mastery

Bonus step: Mastery+

Step 1: Discovery

The first step is all about understanding the landscape. You need to know what you’re up against before conquering it.

Key Activities

Research different types of case interviews and consulting firms.

Identify the skills commonly tested.

Conduct informational interviews with current consultants (this can also be an opportunity to validate whether consulting is a good fit for you).

Major Pitfalls to Avoid

Don’t assume all case interviews are the same.

Avoid neglecting the importance of networking early on.

Don’t underestimate the emotional job; build your confidence from the start.

Step 2: Practice

You’ve done your homework; now it’s time to get your hands dirty. Practicing case interviews is where you turn knowledge into skill.

Work on mock case interviews with peers or mentors.

Use case interview prep books and online resources to practice cases.

Track your performance to identify areas for improvement.

Don’t practice going through the motions; make each session count.

Avoid practicing only with friends who might not give honest feedback.

Don’t ignore your weaknesses; confront them head-on.

Step 3: Mastery

This is the final stretch. Mastery is where you develop and fine-tune your skills to become a top 1% candidate.

Think using first principles .

Seek feedback from industry professionals.

Develop your business acumen:: while you are not expected to have an in-depth knowledge of an industry, a high-level understanding will help to generate better ideas and insights.

Practice with a diverse set of cases (different situations and industries).

Practice with recent cases (read the section Old vs. New cases).

Conduct mock interviews under timed conditions.

Do you know the Dunning-Kruger effect?

If not, read this article because it can be what you need to land offers in consulting.- Don’t get complacent; always look for ways to improve.

Therefore, avoid the trap of overconfidence; humility can be your greatest asset.

Step 3bis: Mastery+

Think you’re ready?

Mastery+ is your chance to test your skills in a lower-stakes environment by practicing with Plan-B firms.

Yes, you read me well: practice case interviews with Plan-B firms.

Apply to consulting firms that are not your first choice.

Go through their interview process as if they were your top choice.

Use the experience to identify any remaining gaps in your preparation.

Don’t treat these interviews as mere practice; give them your all.

Avoid burning bridges; you never know when a Plan B could become a Plan A.

Don’t ignore feedback; even a rejection can be a valuable learning experience.

From Discovery to Mastery+, each step is a building block towards your ultimate goal: acing that case interview and landing your dream consulting job.

Many candidates without business or consulting experience did it, and so can you.

So, are you ready to embark on this transformative journey?

Start by learning how to solve case interviews and get tips to help you navigate this exciting path.

Finally, watch this video about how to prepare for case study interviews on the BCG website :

BCG how to prepare for case interviews

Frequently Asked Questions

How much time is needed to prepare for case interviews.

This is a tricky question.

Because it depends on factors such as:

Your strengths and weaknesses

The time you can dedicate to your preparation

Your learning pace

However, there is an important rule:

Start as soon as you can.

It takes time to be ready.

A case interview is NOT an exam: you can’t cram your consulting interview preparation in a week or two.

What are the most common case interview mistakes?

Check this article to find out what are the 16 case interview mistakes to avoid at all costs.

What are the differences between Round 1 (R1) and Round 2 (R2) cases?

Here are the main differences between first round interview and second round interview:

The seniority of your interviewers : R2 case interviewers are often Directors or Partners, while R1 case interviewers are Senior Consultants or Managers

Stress : Second-round interviews are usually more stressful. The reasons are numerous: the offer is getting closer and closer, interviewing with a Partner from a prestigious firm, etc.

Competitiveness : R2 candidates are competing with other R2 candidates. This tautology means that all the candidates who have made it so far are good, and the selection will be made on details.

The weight on assessment criteria : R2 assessment criteria are the same as R1 criteria (see the section “What do case interviewers look for?”). However, the importance of these criteria differs. Partners tend to value more criteria such as communication, confidence, leadership, and maturity.

Focus on your weaknesses : after an R1 case interview, the consulting firm lists your strengths and weaknesses. Therefore, an R2 case interview includes questions to validate (or invalidate) any doubt about your capacity to be a world-class consultant. For instance, if your quantitative performance was not positive, you can expect an R2 case interview with many quantitative questions.

However, I believe these differences should NOT influence your interview prep.

And, as discussed in this article, your goal is to be in the top 1% across the 4 main performance assessment criteria.

Finally, since we are talking about R2 interviews:

I can not stress enough the importance of fit interviews.

Your answers to questions such as “ Why consulting? ” or “ Why McKinsey? ” greatly influence the final decision.

Will my case interview be in person or via Zoom?

Check with your HR contact to validate this point.

Besides, you can read this McKinsey guide about virtual interviews.

Do you recommend practicing with a coach?

Being a coach myself, I’m obviously biased.

But I tried to give you a fair answer to help you decide what’s best for you.

First, let’s define what a good coach is.

A coach is someone with an extensive experience in consulting and in helping others land offers.

For instance, your friend who just got an offer at McKinsey is NOT a coach.

Receiving an offer and explaining to others how to receive offers are two different things.

Therefore, the first criterion to decide if a coach can help you is to look at how much time they spend in:


Supporting candidates.

That being said, I recommend using coaching services if you can afford it.

Because this is the best way to get qualitative feedback.

You’ll know PRECISELY:

What is the distance between your performance and the performance of the top 1% of candidates.

How to quickly reduce this distance and become a top 1% candidate yourself.

At careerinconsulting.com, we have a unique coaching model:

We coach and support our clients until they receive an offer.


If yes, check this page .

What are the basic business concepts to know?

I’ve written an article discussing some basic business concepts that might be helpful in acing your case interviews.

Any final tips?

Check these 16 case interview tips to move your skills to the next level.

For instance, you’ll learn the mistakes to avoid when developing an issue tree.

Also, check these case interview examples by clicking here .

How to get a case interview?

You get it:

Acing case interviews require a ton of hard work.

And you don’t want to put all this hard work into the trash by not being invited for interviews .

Unfortunately, the odds are against you: less than 30% of applicants are invited for interviews.

The application funnel in consulting

And don’t fool yourself:

Your prestigious college name and high GPA are insufficient.

Consulting firms look at a combination of factors to select the applicants invited for interviews.

So, how to pass the screening phase and be invited for interviews ?

But don’t worry, I’ve written comprehensive guides that tell you how to do it.

Write a consulting resume

How to make your resume stand out?

By writing EPIC bullet points!

So, check this step-by-step guide to turn your resume into an outstanding resume.

In this comprehensive guide, you’ll learn:

What matters the most to recruiters in consulting

How to stand out from the hordes of other applicants

What are the most common mistakes that lead to rejection (and how to avoid them)

Also, you can download templates for McKinsey, BCG, and Bain & Company.

And here is the best part:

You’ll get an exhaustive checklist to assess the readiness of your CV.

Write a consulting cover letter

At the beginning of the interview process, recruiters from top consulting firms want to know you better.

They want to know who the person is beyond the amazing achievements on your CV.

So, if you wonder how to express your motivation to join a firm, this step-by-step guide is for you.

Also, you can download winning cover letter examples that passed the screening phase at top consulting firms.

See you there !

Beyond case interview prep: Fit interview questions

Your case interview performance counts for 50% of the interviewer’s decision.

The other 50%?

Your fit interview (aka personal experience interview) performance.

So, you can’t overlook your personal experience interview preparation.

Are you in one of the following situations?

I’ve just been accepted at [fancy MBA program]. So, I know how to present myself.
I’ve just been accepted at [fancy non-consulting company]. So, I know how to present myself.
I’ve had lots of job interviews in the past. This is not new to me. Instead, I prefer to spend my time on case interview preparation because case interview is new to me.

Your preparation must be aligned with the specific requirements of consulting firms.

In other words, even if some questions are typical job interview questions (e.g., “Tell me about yourself”), their expectations are different.

For instance, consulting firms assess your strategic thinking skills even in fit interviews.

Besides, they want to understand why you are genuinely interested in pursuing a career in consulting.

Thus, here is a series of articles to help stand out during your fit interviews:

How to answer the “ Tell me about yourself ” question

How to answer the “ Why consulting ” question

How to answer the “ Why Mckinsey or BCG or Bain ” question

How to answer behavioral interview questions using the STAR framework

Read these articles, and you’ll be covered for the main personal experience interview questions.

McKinsey PEI - the three types of PEI questions

Case interviews mimic what consultants do: solving business problems.

And often, there is no right answer.

What’s important is to show how you think.

So, I hope this guide will help ace your consulting interviews and start your career in management consulting at Boston Consulting Group or any top consulting firm.

I’d love to hear from you: What’s your biggest challenge in case interview prep?

Let me know by leaving a quick comment below right now.

-Want to know all the secrets of the consulting interview process?

👉 Check this article about the McKinsey recruitment process .

👉 Also, check this article about the Boston Consulting Group recruitment process .

Want more case interview examples? Or start to practice cases?

👉 Check this page: https://careerinconsulting.com/case-interview-examples/

You’ll find plenty of Bain case interview examples, for instance.

Finally, want to ace personal experience interview questions?

👉 Check this page: https://careerinconsulting.com/mckinsey-pei/


4 thoughts on “Case interview prep: The definitive guide”

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consulting case study calculation

Hi Sebastien, thank you for your informative article. I do struggle to assign 7 McKinsey cases into the above-provided groups, they seem to get a bit more creative every year! Do you mind commenting or advising on those?

Case/Type: 1) Case: Beautify, Potential Type: Take a strategic decision 2) Case: Diconsa, Potential Type: Take a strategic decision 3) Case: Eletro-Light, Potential Type: Take a strategic decision) 4) Case: National Education System, Potential Type: ? 5) Case: Talbot Trucks, Potential Type: Take a strategic decision 6) Case: Shops Corporation, Potential Type: ? 7) Case: Conservation Forever, Potential Type: ?

consulting case study calculation

Hi. thank you for your message. Where can I find the above cases?

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How To Write A Consulting Case Study: Guide, Template, & Examples

When you deliver a successful project, do you publish a consulting case study about it?

A consulting case study is a short story about a successful project that explains…

  • The problem your client was dealing with before hiring you;
  • your expertise and process for solving that problem;
  • and the results your expertise and process created for the client and their business.

In my experience, our consulting case studies are among the most powerful pieces of content we publish. They’re a big reason why people are comfortable signing up for our Clarity Coaching Program .

Because our case studies prove our program helps our clients get results.

I can say that our coaching program is the best on the market until I’m blue in the face.

But it’s much more powerful for consultants to see the results others have experienced for themselves: through our case studies and testimonials.

If you don’t have something of value on your website like a case study — something that actually shows you can achieve results for your clients — then your website will only serve as “confirmational marketing.”

It will confirm what people hear about you. But it won’t help you generate interest and leads.

So, if you want to shift your website beyond mere confirmational marketing to an asset that helps you generate leads and conversions, consider writing consulting case studies using the method below.

In this article, you’ll learn how to write compelling case studies that help you win more consulting clients.

Ready? Let’s dive in…

Your case study is proof that not only can you talk the talk, but you can also walk the walk.

What Is A Consulting Case Study?

When a potential client is deciding on whether they will hire you or not, a big question in their mind is…

“Can this person or company really do what they say they can for my business?”

There are many forms of thought leadership you can use to prove you can deliver results.

The consulting case study is one of them.

A case study, in the context of consulting, is typically a written document that describes…

  • the problem a client was facing,
  • the actions you took to solve that problem,
  • and the outcomes it created for your client.

You write case studies to demonstrate the results and value you created for a past or current client.

What makes them so effective as marketing material?

  • They are relatively easy to put together (especially when you use our template below).
  • Your potential clients enjoy reading them.
  • And they are a highly effective way to demonstrate your authority and expertise in your field.

Next, I’ll walk you through how to write a consulting case study.

In our program, one of the things we teach consultants is how to better understand their clients’ problems and articulate their ability to solve those problems in a way that will attract new clients.

How To Write A Consulting Case Study

Here are the steps to writing your consulting case study. You can follow along with our consulting case study template .

1. Get Permission From The Client

You shouldn’t write a case study that names your client without their permission.

So, before you start writing it, ask them if they’d be OK with you publishing a case study about the project.

Now, I’m not a lawyer, and nothing in this article or anything I write is legal or financial advice. But here’s what we’ve found, through running consulting businesses for over two decades, often works best:

A question we often receive from consultants is “What if I can’t use the name of my client or the company I worked with?” Generally, this isn’t an issue. If your contract says you can’t use the client’s company name, or the client says “No” to your request, all is not lost.

What tends to work extremely well is still writing the case study, but without using the client’s name. Instead, describe the client.

For example, let’s say your client is the automaker Mazda. If you can’t use their name, consider “Working with a top 20 global automaker…”

This gives prospective buyers a good idea of the caliber and type of company you worked with.

When you ask your client for their permission to create a case study that features them, you’ll generally find that 9 times out of 10 they won’t have a problem with you doing so, but make sure you ask before publishing.

2. Introduce The Client’s Business

Once you’ve gotten permission from the client, you’ll begin writing your case study. Follow along using our template .

The first section is the introduction. Set the stage here by introducing your client, their business, and their industry.

This section gives context to the case study. Ideally, your ideal client is intrigued by being in a similar industry or situation as the client in your case study.

3. Describe The Problem Or Challenge

In this section, you outline the problem your client was facing.

Be as specific as you can be.

Simply saying they had marketing issues or a problem with their PR is not enough.

The more detail you include the clearer the picture will become and the more effective your case study copywriting will be.

If your ideal client reads this and has a similar problem as the client in the case study, you can guarantee that their eyes will be glued to the screen, salivating to learn how you solved it.

4. Summarize Your Action Steps

Now that you’ve described the problem your client was up against, you’ll explain what you did to help solve the problem.

In this section, break down each part of the process you used or the steps you took to solve it.

The reader should get the sense that you have a process or system capable of solving the problem and getting results.

This is where you get to demonstrate your know-how and expertise. Get as technical as you can. Show your reader “Hey, this is how I can get YOU results too.”

5. Share The Results

It’s time to demonstrate results.

Write the results that were achieved and how they impacted the business/organization/person.

In many cases, the outcome isn’t just dollars and cents — it can also be less tangible value.

Are they less stressed? Do they have more free time? Are they finding more meaning and enjoyment in their work?

Mention if you’re continuing to work with this client through a retainer . If you’re not, describe how the results will impact their business in the future.

This is also a great place to include a quote or testimonial from your client.

The “Results” section is key because it shows prospective clients that you’ve solved the problems they are facing and have delivered the actual results that they likely desire.

6. Write A Call To Action

At the end of the case study, you should always include a sentence or two inviting the ideal client to reach out.

They’ve just read about the problems you can solve, how you solve them, and the results you can create.

They are primed and ready to reach out to inquire about how you can do it for them.

But if you don’t have a direct call to action for them to do that, many of them will leave without taking action.

So, write a direct, clear call to action that takes them to a page where it’s easy to book a consultation with you or where you provide your contact information.

7. Share It

Marketing for consultants is all about providing value to your ideal clients, being known for something specific, and positioning yourself as an expert and authority that your ideal clients want to work with. So, whenever you publish a piece of valuable content like a case study, your mission is to get as many eyes on the case study as possible.

The best place to publish your case study is on your website or blog.

You can also submit case studies to industry publications. These are a great way to spread the word about you and your client’s business.

Make sure to also share your case study on all social media platforms where your ideal clients hang out online. For consultants, that means LinkedIn.

Work your “marketing muscle” by actively promoting your case study, and you’ll reap the rewards of this powerful piece of authority-building content.

Writing case studies for your consulting business not only helps you land new clients, but it’s also a great way for you to review past projects.

Doing this helps you to find what worked and what didn’t.

And you’ll continue to learn from your experiences and implement your best practices into your next consulting project.

Consulting Case Study Template

Click here to access our Consulting Case Study Template .

consulting case study template

This template is designed using a “fill in the blank” style to make it easy for you to put together your case studies.

Save this template for yourself. Use it to follow along with the examples below.

Consulting Case Study Examples

Here are some example case studies from our Clarity Coaching Program clients.

1. Larissa Stoddart

Larissa Stoddart teaches charities and nonprofits how to raise money.

To do that, she provides her clients with a training and coaching program that walks them through twelve modules of content on raising money for their organization, creating a fundraising plan, putting an information management system into place, finding prospects, and asking those prospects for money.

how to write a consulting case study example

Through her case studies, Larissa provides a comprehensive overview of how she helps her clients build robust fundraising plans and achieve and win more donations.

2. Dan Burgos

Danila “Dan” Burgos is the president and CEO of Alphanova Consulting, which works with US manufacturers to help them increase their profitability through operational improvements.

The goal of Alphanova is to increase their clients’ quality and on-time delivery by 99 percent and help them increase their net profits by over 25 percent.

manufacturing consultant case study example

Through his case studies, Dan lays out the problem, his solution, and the results in a clear simple way.

He makes it very easy for his prospects to envision working with his firm — and then schedule a consultation to make it happen.

3. Vanessa Bennet

Through her company Next Evolution Performance, Vanessa Bennett and her business partner Alex Davides, use neuroscience to help driven business leaders improve their productivity, energy, profitability, and staff retention, while avoiding burnout.

consultant client work webpage

Through her “Clients” page, she provides a list of the specific industries she works with as well as specific case studies from clients within those industries.

She then displays in-depth testimonials that detail the results that her consulting services create for her clients.

These are powerful stories that help Vanessa’s clients see their desired future state — and how her firm is the right choice to help them get there.

As you see, our clients have taken our template and made them work for their unique style, clients, and services.

I encourage you to do the same.

And if you’d benefit from personal, 1-on-1 coaching and support from like-minded consultants, check out our Clarity Coaching Program .

Get Help & Feedback Writing Consulting Case Studies

If writing and demonstrating your authority were easy, then every consultant would be publishing case studies.

But that’s not the case.

Sometimes it helps to have a consulting coach to walk you through each step — and a community of like-minded consultants with whom you can share your work and get feedback from.

That’s why we’ve built the Clarity Coaching Program.

Inside the program, we teach you how to write case studies (among dozens of other critical subjects for consulting business founders).

And we’ve also created a network of coaches and other consultants who are in the trenches — and who are willing to share their hard-fought knowledge with you.

Inside the Clarity Coaching program , we’ve helped over 850 consultants to build a more strategic, profitable, and scalable, consulting business.

Learn More About Clarity Coaching

We’ll work hands-on with you to develop a strategic plan and then dive deep and work through your ideal client clarity, strategic messaging, consulting offers, use an effective and proven consulting pricing strategy, help you to increase your fees, business model optimization, and help you to set up your marketing engine and lead generation system to consistently attract ideal clients.

15 thoughts on “ How To Write A Consulting Case Study: Guide, Template, & Examples ”

This is a great outline and I found it quite helpful. Thanks.

Shana – glad you found this post helpful!

I have used case studies to get new clients and you're right, They work.

Jay – thanks for sharing. I've worked with many clients to implement case studies and have used them in several businesses and have always found them to be great at supporting proof and establishing authority and credibility.

Dumb question: guess you can't charge if you're doing a case study, huh?

Terri – No such thing as a dumb question where I come from. Always good to ask.

You definitely can charge for case studies. Michael Stelzner has a lot more information on writing white papers (and case studies) as projects.

This post was really aimed at using case studies to win more business and attract clients. But you can definitely offer this service to companies and they'll pay handsomely for it.

That was a great question!

Hello,I am really glad I stumbled upon your consulting site. This outline is very helpful and I love the e-mails I recieve as well Thanks!

Happy to hear that

This is a great site for consultants – great information for the team to share with consultants that reach out to us. Thank you!

Thanks Deborah

It is a good steps if we know how we start and control our working.

All I wanted to know about putting together a case study I have got. Thanks so much.

to put together your consulting case study: to put together your consulting case study:

I have used your outline today to write one case. Thank you for sharing.

Hi – This is a great piece, and covers all the core elements of a case study with impact.

Couple of extra points…

1. it’s really powerful to provide a mix of qualitative and quantitative results where possible e.g. ‘we saved the client $500 per month and feedback tells us morale improved’

2. We are seeing more and more consultancies include images and video in their case studies. This obviously depends on the context, so while it’s not necessarily appropriate within the confines of a bid, it is definitely something to think about for those case studies that you want to publish online or in a marketing brochure.

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consulting case study calculation

Case Interview 2024 – Guide for Your Consulting Case Interview

A case interview is a type of job interview in which the candidate must analyze and solve a problematic business scenario (“ case study ”). It is used to simulate the situation on-the-job and to find out if the respective candidate meets the necessary analytical and communications skills required for the profession. Case interviews are commonly and globally used during the selection processes at  management consulting firms such as McKinsey , Boston Consulting Group (BCG), or Bain & Company . It is the most relevant part of the process for consulting jobs, and they are usually based on projects that the hiring firm has delivered for a client. It is an exercise that requires a logical approach to finding the problem and an appropriate solution.

  • 1. Case Interview Questions and Answers
  • 1.1 What Is a Case Interview?
  • 1.2 Who Uses Case Interviews and Why?
  • 1.3 What Are the Skills Required in a Case Interview?
  • 1.4 What Are the Differences Between …?
  • 2. Case Interview Examples from Top Consulting Firms
  • 3. Case Interview Frameworks
  • 3.1 The Best Frameworks for Solving Cases
  • 3.2 How to Develop Your Own Framework in 4 Steps
  • 4. Case Interview Preparation: 9 Tips for Successful Case Preparation
  • 5. How to Solve a Case Study in 10 Steps
  • 6. Case Interview Secrets: 13 Final Tips for Your Actual Case Interview 
  • 7. PrepLounge: The Key to Your Success 
  • 8. Get Started Right Away and Practice Your First Cases

consulting case study calculation

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A  case interview  is part of the job interview process in which you as the candidate have to analyze and solve a problematic business scenario while interacting with the interviewer. The case study is often based on a problem the interviewer has worked on in real life. This part of the interview is intended to be more of a dialogue. You will need to be proactive and ask questions when attempting to close in on the correct conclusion. Oftentimes, the consultant will attempt to guide you in the correct direction by asking questions himself.

An example question might be :​ The CEO of Deutsche Bank has become increasingly concerned about their declining profitability over the last 36 months and has asked you to determine the factors causing the decline as well as recommend a strategy to reverse this trend.

During the entire application process, you will partake in  up to six case interviews  in two rounds or more. This is dependent on the position you are applying for. Most case interviews have the same underlying structure. An individual case interview may take up to an hour and usually consists of four parts:

Case Interview Format

Case interviews have always been a part of management consulting interviews. Nowadays, also marketing, strategy, operations, or retail positions tend to use similar formats because they are a great tool to probe the quantitative and qualitative skills of an applicant . It allows interviewers to get a deeper insight into how you present yourself as a candidate and apply the limited amount of information given to you.

The reason for the prevalence of the case interview format in management consulting is that the topics and themes handled in most cases reflect conditions close to the reality of the day-to-day activities of a consultancy. It requires the applicant to  ask the right questions , apply  structured frameworks,  and think outside the box . As a consultant, you will spend a lot of time client-facing, and so soft skills are just as important as hard skills to the interviewer. The case interview allows hiring companies to ask the question "Would I be happy to put this candidate in front of a client?".​

Due to the scenario set up in a case interview, it is also a test of general business acumen. Many consultant projects will be in industries where the consultants aren't experts, especially junior consultants. This is normal, but to be effective as a consultant business acumen is an important foundation for consultants to maintain effective strategy recommendations. Companies pay consultants for their minds rather than their industry expertise.

Case Interview Skills

A case interview has no “correct” or “standard” answer. There are often many solutions to a single case and in the end, what counts is your train of thought and how you got to your solution. The interviewer will evaluate you across five main areas:

1)  Problem-Solving Skills 

The interviewer will analyze your ability to identify problems , isolate causes, and prioritize issues. During a case interview, you will be presented with a wide range of relevant and irrelevant data pieces. You must know how to use this data to make your recommendations and you have to prove that you are able to construct a logical argumentation without rushing to conclusions based on insufficient evidence.

2)  Creativity and Business Sense Skills 

As a consulting candidate, you should know the basic business concepts as well as show a certain amount of business sense and creativity. If the interviewer asks you to find innovative ideas to increase the profitability of a hotel chain, you will have to come up with a range of ideas that make business sense. You are not expected to have deep knowledge of the hospitality industry, but to be able to ask relevant and insightful questions on the aspects important for you to solve the client’s issue at hand.

3)  Structure 

Maintaining a structure means that you solve the question with a clear step-by-step approach that you communicate actively with your interviewer. A good structure is the most important part of a case interview, as it is the underlying base of your whole approach and argumentation. It is also the main reason why candidates fail their case interviews. A common mistake that candidates make is that they try to apply standardized frameworks to any case they are given. Instead, you should solve each case by creating a framework specifically tailored to its needs – as you would do as a consultant on the job. Practice your structure with our Structuring Drills .

4)  Math Skills 

As a consultant, part of your job is number-crunching and interpreting data. Therefore, it is important that you have a good feeling for numbers and have great mental math skills. You should be able to perform simple calculations in your sleep. You can practice your math skills with our Mental Math Tool .

5)  Communication Skills 

In times of digitalization, soft skills become more and more important for management consultants. On the job, you will be in contact with high-level CEOs, clients, partners, and colleagues. Strong communication is crucial for you to get your work done efficiently. Thus, your interviewer will pay close attention to the way you communicate and present yourself during your conversation. Always be professional, answer concisely, and communicate the key message first (see Pyramid Principle ).

First and Second-Round Interviews 

While the format of the first and second-round interviews stays the same, the seniority level of the interviewer differs . The person interviewing you in the first round is usually more junior, having up to four years of consulting experience (Associates or Engagement Managers). The second round is led by Partners who have more than ten years of experience and tend to drill you to understand how you cope with challenges. Therefore, second rounds are perceived as more difficult by candidates. Since partners have a stronger voice when discussing an applicant, your performance during the second round of case interviews carries also more weight. For more information on the different positions, please read McKinsey Hierarchy: The Different Position Levels .

Candidate- and Interviewer-Led Case Interviews

In candidate-led cases, the interviewer expects the candidate to lead him/her through the case. As a candidate, you can do so by asking relevant questions, and by developing and testing your hypotheses. Candidate-led cases are the most common  types of cases . You will encounter them at the majority of the big consulting firms such as BCG, Bain, and occasionally at McKinsey.

Interviewer-led cases are most frequently used at McKinsey. As the title suggests, the interviewer’s guidance through the case interview is firmer.

You can find more information on the two different interview styles in our BootCamp article: Interviewer-Led vs. Candidate-Led .

In the following, you can find some examples of initial case interview questions :

consulting case study calculation

Bain Case: Old Winery You inherit an old winery, the Old Winery, from your grandfather. Since you have little knowledge about wine cultivation, you don't want to run the winery operationally, but you find the idea of owning a winery exciting. However, your plan is to breathe new life into the winery. Read the entire case .

Deloitte Case: Footloose Duraflex is a German shoe manufacturer with an annual turnover of approximately €1 billion. Your largest sales market has always been the boot market. In this market, you compete with three other main competitors. Management is asking you for advice. Read the entire case .

consulting case study calculation

Roland Berger Case: Onlinestar Onlinestar, an online retailer specializing in furniture and garden products (core business), has experienced significant growth in recent years due to an expansion of its product portfolio. The board of Onlinestar is asking you for an analysis of the reasons for the negative results, as well as recommendations derived from it. Read the entire case .

Practice More Cases Now!

You can find more than 160 case studies, including cases from real companies and our consulting coaches, in our Case Library !

consulting case study calculation

Case interview frameworks are the perfect tool to structure your thoughts during the interview. They help you break down a problem into its components so that you can systematically and methodically navigate through the case and the business problem. This approach will convince your interviewer that you can apply your skills from the case interview to the job as well.

A framework can help you solve a business problem in a case interview in a structured and organized manner. To determine which framework is most suitable for the given case, you should be familiar with the most common case types. Our coaches Guennael and Vlad explain their approaches:

What does a framework really need to accomplish? Essentially, three things:

First , it must be MECE (Mutually Exclusive, Collectively Exhaustive); second , it must help you systematically and methodically approach the case so that you not only find the best answer; third , it must convince your interlocutor that your success is repeatable and that you will solve this case and the next and the one after that.

When preparing for my BCG interview, I ultimately relied on just two framework concepts, which I then adapted to the respective case: First, a version of the profitability case (Profit = Revenue - Costs and Revenue = Price x Quantity) ; second, a basic version of: Product, Price, Customer, Competition, Company).

Are these two framework models optimal in every case? No, they are not. Did they serve their purpose? I used them in more than 10 practice cases with former BCG employees as well as in my 5 BCG cases... and I succeeded, that's for sure :) I would even argue that every case can be solved using one or both of these methods . Learn them, keep them in your pocket, and be ready to use them. If you find something better, great! But I'd prefer you start with an "okay" framework and focus on solving the problem , rather than spending the first 30 seconds of the case trying to find the "perfect" framework, failing, and feeling forced to think on the fly at the beginning of the solution process.

There is no universally applicable structure . You should have some patterns in mind for specific types of cases, but you should adjust them depending on the case:

Additional details of the case

Below you'll find a list of the most common case types and some general recommendations for structuring :

Market Sizing - Structuring from the supply or demand side. Structuring based on a formula or a issue tree .

Profitability - Basic profitability framework. Consider different revenue streams and the product mix.

Market Context (market entry, new product, acquisition, etc.). Always start with the big picture "market". Conclude with a specific strategy to achieve the case objective (e.g., "market entry strategy" - for market entry. "Exit strategy" for the PE case. "Go-to-market strategy" for a new product). Structure it as if you were defining the workflows for the real project.

Operational Mathematical Problem (e.g., Should we increase the speed of an elevator or simply buy a second one? How should we reduce queues? Etc.) - Structuring as a process/value chain, with inputs, processes, and outputs.

Cost Reduction - here are some recommendations for structuring:


How do the costs break down and what are the largest costs?

Benchmarking the largest costs to identify improvement potential

Process improvements to achieve the benchmarks

Costs and benefits of the proposed initiatives

The key concepts you must learn:

Internal/external benchmarking

Core processes (usually optimized) and supporting processes (usually trimmed)

Mathematical structures (frequency of operations * time per operation)

Other useful structures (e.g., People - Process - Technology)

Evaluation - Pure financial structure with cash flows, growth rate, WACC / Hurdle Rate, etc.

Synergies - Revenue synergies (price, quantity, mix) and cost synergies (value chain).

Social/economic cases (e.g., How can the quality of life in the city be improved? How can museum revenue be increased?) - significant variability.

Practice 3-5 social cases before the interview. Additionally, there are s everal useful framework concepts that you can apply in the middle of the case to find the cause of a problem. For example:

People - Processes - Technologies

Capacity - Utilization - Production rate

Product - Distribution - Marketing - Price

Value-based pricing - competition-based pricing - cost-based pricing

You will learn these frameworks while solving cases. It is useful to have a set of them in mind to quickly identify the root cause .

To be able to address specific questions in case interviews, it is important to develop your own frameworks . Our expert Benjamin has valuable tips on this.

(Almost) Never use a standard framework from the books . In strategy consulting, the goal is to assist clients facing unique problems with a customized solution. It's unlikely that you can force your approach into a standard framework.

Put yourself in your client's shoes and show empathy for the issues. This way, it becomes much easier for you to understand what the key issues are that you need to consider when formulating a recommendation, and you can ensure that you don't forget anything. I always ask myself, "What would I do if this were my company and my own problem? What do I need to know/understand to make a decision?"

Ensure that every topic you want to address is relevant to the final recommendation. A simple check is to ask yourself, "If I spend time on this specific topic and get some answers to my questions (e.g., market size, competition, etc.), will this provide useful elements for the final recommendation given my client's issues ?" If the answer is no, then you should skip this subtopic.

Practice a lot! The above tips come from my own experience with building MECE structures , but keep in mind that it takes a lot of practice to achieve satisfactory performance here.

1. Learn the Theory By reading this article, you've already taken the first step to understanding what case interviews are all about. Well done! You can now take it a step further by learning the theory you need to solve the cases. In general, you should learn how to :

Identify your case type (e.g., market sizing , market entry , profitability , growth )

Structure your thoughts (e.g., issue tree , MECE , pyramid principle )

Use business analysis tools (e.g., ABC analysis , break-even analysis , benchmarking )

Define common business terms (e.g., NPV , CAGR , fixed and variable costs )

In our Case Interview Basics, you'll find all the necessary fundamentals.

2. Develop Your Business Intuition Step by Step

Since you need to have a good business sense to successfully complete your case interview, you should invest some time beforehand to gradually build up your business intuition. The earlier you start, the easier it will become. Make it a habit to regularly read business publications and magazines. You can read new releases from McKinsey, Bain, and BCG, or find other sources that appeal to you. Try to acquire a basic understanding of economics, strategy, and industries, such as retail, airlines, telecommunications, banking, natural resources, and technology.

3. Update Your Math Skills

For all case interviews, you must calculate without a calculator. Therefore, refreshing your mental math skills should be a regular part of your daily preparation plan. Practice until you feel one hundred percent comfortable with the basic skills of addition, subtraction, division, multiplication, and growth rate calculations in your head. Read our article on Fast Math and use our mental math tool to train your performance. When confronted with a math problem in your case interview, this will significantly reduce the pressure.

Knowing shortcuts for a variety of calculations can simplify mathematical problems. For example, break down complex mathematical problems into several small operations:

97 x 53 = (100 - 3) x (50 + 3) = 5000 + 300 - 150 - 9 = 5141

4. Practice Makes Perfect

Take a look at our extensive case library , which prepares you for all possible case types. Our case library includes cases that have been used in past case interviews. Solving cases on your own can give you a first sense of what to expect in the case interview. However, the only way to improve your skills to successfully pass the interview is to put yourself in a case interview situation. Find candidates to practice with and practice regularly. The more feedback you can get, the better. This will help you improve.

PrepLounge offers the world's largest case interview community. Simply schedule or accept a practice interview with other candidates on our meeting board .

Here's how it works:

Schedule: Once you and your case partner confirm the practice interview on the meeting board, the meeting is set and will be visible on your dashboard.

Communication: We recommend contacting your case partner directly to discuss communication methods and case preferences during the interview.

Interview: During the back-to-back meeting, you and your case partner take turns playing the roles of both interviewer and interviewee. Don't neglect the part of the session where you play the role of the interviewer. This allows you to identify important points and adjust your approach accordingly.

Case: By default, two PrepLounge cases are randomly selected. However, you can exchange them and choose one of our over 180 cases or use your own case.

Feedback: This is the most important part of your practice interview as it helps improve your case performance. Please provide your interview partner with constructive feedback, just as you would expect from them.

5. Seek Support from Experts

To make your case interview preparation as effective as possible, we also recommend investing in coaching sessions with experienced top consultants. Our experience shows that this investment pays off, as it significantly increases your chances of receiving an offer for your dream job (by four times, to be exact). Our experts know exactly what interviewers want and can work with you on every aspect of your case performance, whether it's structuring, personal suitability, confidence, or communication. Furthermore, they can provide you with valuable networking tips and help you get a referral.

We provide you with a transparent list of all case interview coaches, including their professional and educational background, top skills, individual approaches, ratings, and recommendation rates. This way, you can individually select the perfect expert for your coaching sessions . Additionally, you can benefit from CoachingPlus , which includes a premium membership and a generous discount (compared to individual coaching sessions).

6. Learn and Track Your Progress

You can do as many cases as you want. If you don't learn from them, you won't improve your case performance. That's why you should do the following: At the end of each case you complete, whether on your own, with a case partner, or with an expert, write down in your own words what mistakes you made and what you learned. Repeat the case after a few days and apply what you've learned to ensure you're making progress. Tracking your progress motivates you and ensures you don't repeat the same mistakes.

7. Don't Forget the Personal Fit

No matter how well you master the case, if you don't personally fit into the company, you won't get the job offer. Ultimately, consulting is a "people's business" that involves teamwork and a lot of time with your colleagues. To master the part of the interview that focuses on personal suitability, it's important to understand what an interviewer is looking for in a candidate to decide if they fit into the company personally. Typically, the interviewer has three primary questions in mind.

Next, you should learn how to convey to your interviewer that you fit what they're looking for. Practice your answers to the personal fit with other candidates or experts:

Why consulting?

Why company X?

Why should we hire you?

Tell me about yourself!

Give me an example of when you led a group to achieve a difficult goal!

Find more frequently asked questions in stress question mode.

8. Train Confidence

The more you practice, the more confident you will feel. However, feeling confident isn't the same as appearing confident. Sometimes you can come across as insecure without realizing it. This can be due to small habits in your communication style. Therefore, ask your PrepLounge case partner or expert to consider your verbal and non-verbal communication and provide feedback on your confidence or insecurity . Focus on the following aspects during practice:

  • The tone of your voice. A monotone voice or speaking too quickly gives an impression of insecurity and poor communication style. To avoid this, it's helpful to listen to podcasts of great speakers for 30-60 minutes a day. After a few days, you'll start speaking in a similar manner as you adopt their communication style.
  • Smile. A smile can be a powerful way to show that you're enjoying the conversation and not afraid. You can also force a smile (naturally, not too much) if you get feedback that you appear too serious.
  • Eye contact. You don't need to continuously stare into the interviewer's eyes during the conversation, but you shouldn't look away when they ask you something.
  • Ability to break the ice. Confident people aren't afraid to engage in small talk with interviewers. Silence creates less connection and can be seen as a sign of lack of confidence.
  • Posture. You should try to sit upright most of the time on your chair. Leaning too much towards your interviewer can be interpreted as lack of confidence.

9. Take Breaks

Overall, based on our experience with other case partners, you should prepare for an average of 50 hours over a period of up to 6 weeks and practice daily. This can be exhausting, and we know that many candidates struggle with motivation and concentration, especially after an intense case preparation period. This is usually because they forget to incorporate regular breaks into their preparation plan. Professional athletes, for example, always take time to rest and allow their muscles to regenerate. You should treat your brain muscles the same way. A good strategy is to develop an evening and morning routine that allows you to relax and increase your energy level for the preparation period during the day. Here are some examples of what you can do:

15-20 minutes of exercise in the evening or morning

A cold shower in the morning

Meditation or journal writing

Define three important things for the next day and allocate time for all activities, prioritizing the most important ones first

No social media for an hour after waking up and before going to bed

Get enough sleep (at least 7 hours)

Take breaks between each case or intensive case practice and do something completely different (e.g., workout, play video games)

10 Steps to Crack the Case Interview Infographic

Step 1: Listen actively and take notes. Write down every piece of information, especially numerical data .

Step 2: Restate the question. Pause, paraphrase, and make sure you understand the problem statement by confirming with the interviewer.

Step 3: Clarify the objectives and identify the problem. Ask specific questions and double-check on objectives. Make sure you completely understand the problem.

Step 4: Write out your structure. Ask your interviewer for a minute to prepare your structure and organize your notes. Identify your case type and use an issue tree to customize your structure. The branches of your issue tree should be MECE .

Step 5: State your hypothesis. Now that you have set up the issue tree, your task is to test each branch to see if it is the root cause of the problem. Where to begin? A hypothesis based on an educated guess helps here.  (e.g. "Since you have mentioned that revenues are more or less flat, my hypothesis is that the problem is mostly driven by the cost side of the business. If it is okay with you, I will start by […]")

Step 6: Think out loud. Sharing your thoughts allows the interviewer to interact. Refine or rebuild your hypothesis as you find out more.

Step 7: Gather more data in order to test your hypothesis. Proactively ask for relevant data and always segment it (e.g. using the ABC analysis ). Try to evaluate whether trends have been company-specific or industry-wide.

Step 8: Dig deeper while staying structured ( MECE !) throughout the case. Always refer to the structure you have set up at the beginning of the case, but be flexible as the case evolves. If you conclude that your hypothesis is false, eliminate that branch and go to the next one. Summarize findings when switching major branches. If your test confirms your hypothesis, go deeper into that branch, and drill down to the lower levels until you identify all proven root-causes.

Step 9: Choose a recommendation and use the Pyramid Principle to structure your conclusion. Ask for a minute to gather your thoughts and then state your recommendation. You need to deliver a one minute, top-down, concise, structured, clear, and fact-based summary of your findings.

Step 10: Stand by your conclusion. Your interviewer will likely challenge your recommendation (either to see if you can handle pressure or to assess if you really believe in what you are saying).

1. Focus on the task at hand 

Don’t think too much about the approach your interviewer is taking. It should not matter much if the conversation is interviewer- or candidate-led. If you go into your interview with a profound understanding of how to handle even a difficult case, the format of the interview should not be an issue. Keep a cool head and structure your thoughts.

2. Ask the right questions 

At the beginning of the case, your interviewer will present you with the situation of the client. Don’t rush into the analysis without developing a deep understanding of the problem first. Ask your interviewer questions to clarify the case. This is expected behavior that also takes place later with the client. Make sure you understand what the  business model  and your  objective  in the respective case are (regarding both money and the timeline). If there are any other possible limitations you are unsure about, ask your interviewer in a concise way. Asking unnecessary questions will raise doubts about your ability to work efficiently under pressure.

3. Buy time with repetitions 

A common trick consultants use is the  repeating of facts or overall goals . By doing this, you are showing a fundamental comprehension of the case and are emitting an aura of control, gradually heading towards a solution. This technique can give you more time to think. Articulating the facts of the case can also be a source of clarity and allow you to form solutions more quickly.

4. Only form a hypothesis with sufficient information 

Do not state a hypothesis at the beginning, a stage in which you may still have incomplete information. Get a good sense of the case’s environment and ask sensible follow-up questions . Only then frame a structure and formulate a hypothesis.

5. Utilize data for your analysis 

Taking wild guesses is a death sentence for your case interview. Make sure your claims are backed up by the facts, and remain calm when presented with new information. Consultancies will closely observe how you  make use of new data and incorporate it into your hypothesis .

6. Take clear notes 

Taking  structured notes  is a highly underrated skill when dealing with a case. Making sure your notes are coherent and clear will make your thoughts easy to navigate and ensure you do not lose your footing during the interview.

  • Place your sheet horizontally to maximize your space, and jot down the case’s  key question on the left side of the page. This way you will never lose sight of the main objective . The remaining portion will be dedicated to the issue tree, with your hypothesis included above the issue tree.
  • Make sure that you highlight key pieces of information that add substance to your hypothesis.
  • When it comes to calculations , use a separate page, but practice having it organized in case you need to go back through your assumptions or calculations.
  • Try to limit the number of pages you use to a  maximum of three sheets . Otherwise, you will stress yourself out while trying to find what you are looking for.

7. Structure is key 

The most important aspect of a case interview is having a good structure. You can structure your case by following these four steps:

  • Craft an issue tree as the overall foundation for your structure. This is a customizable framework used to analyze the root causes of problems in a case. It helps you to break a complex problem down into its components.
  • Make sure that your issue tree is MECE to avoid inefficient dependencies between branches that will slow down your analysis. MECE is a way of segmenting information into sub-elements that are mutually exclusive and collectively exhaustive. 
  • Prioritize and concentrate on high impact issues of your issue tree that will create value for your client. Always make sure you explain the reasons behind your choices to the interviewer.
  • Use the Pyramid Principle to structure your conclusion , a three-step structure to present your synthesis in an effective and convincing manner. First, state the recommendation (What?). Second, provide three reasons supported by data (Why?). Third, provide information on how to implement the recommendation (How?). 

To practice your structure, you can use our Structuring Drills.

8. Don't force-fit frameworks

Standard frameworks can be a source of inspiration, but should never be force-fitted to a case. They are very stiff and do not allow room for customization . If you use pre-defined frameworks, you run the risk of missing important elements of the specific problem you are trying to solve. A consultant would not just force-fit frameworks to their specific client’s problem, so you should not do this in your case interview, either. Each case is unique and requires an individually customized framework that is MECE as well as adapted to the problem you are trying to solve, the company, and the industry.

9. Don’t panic if you get stuck 

If you ever get stuck, don’t freak out – it happens. What counts is how you deal with the situation. Here is what you can do:

  • Take a deep breath  or a sip of water if you have a glass of water nearby.
  • Take a moment to grasp the big picture , to recap what you have learned so far and what you still need to find out to address the main question at hand.
  • Outline how these sub-questions can be answered , and what kind of data or information you will need to do that.
  • Double-check whether data or information provided by the interviewer at an earlier stage is now getting new relevance.
  • Think out loud and take the interviewer along with your thinking process. If you are puzzled by some obvious contradiction, actively discuss this with your interviewer. Oftentimes, an interviewer will wait for you to explicitly verbalize your confusion before gently guiding you.

10. Sometimes there is no clear answer 

Oftentimes, a case interview has no “correct” or “standard” answer. The case may encompass you  exploring the issues and walking down several paths . There are often many solutions to a single case that may differ from the interviewer’s expectations. In the end, what counts is your  train of thought and how you got to your solution . You are not expected to know everything about business, but demonstrate a logical judgment and a good approach to solve problems.

Nevertheless, you should always give a clear recommendation at the end of the interview, when the interviewer will ask for your conclusion. The trick is to use supporting arguments based on what you have learned during the analysis, to point out limitations, and to also highlight additional areas to explore to confirm that your current understanding is the right one.

11. Engage the interviewer 

The interview should be a dialogue, so make sure to engage the interviewer and demonstrate not only your business judgment, but also your communication and people skills . This gives the first insight into how you might interact with future clients and colleagues. How can you do that?

  • Explain. Share your thought process with the interviewer, and always let them know what your next steps are.
  • Listen. During your case interview, the interviewer will usually give you hints and steer you in a direction. Notice that! If they ask a specific question, e.g. “Name three points about…”, answering in two or five points will mean that you didn’t pay attention.
  • Ask questions. Create a discussion, initiate small talk, and use your chance to make a positive connection with the interviewer, especially at the end of every interview when you get to ask final questions. Find a point in common and try to stand out. Here is a list of the best questions to ask at the end of an interview .  

12. Be confident 

You don’t necessarily need to be extroverted to be a top management consultant, but you need to be confident. Consulting is a people job as much as it is an analytical job. It is important for the client to feel that you know what you are doing. Thus, this is something the interviewer will take into consideration. Here are five things you can do during the interview to come across as more confident:

  • Try to enjoy the interview by focusing on the challenge, the satisfaction it brings you when you solve the case, and the joy of sharing your life experiences with someone else. If you have fun, chances are high that the interviewer has fun, as well.
  • Find your own style and don’t try to pretend to be someone that you are not. It is fine if you are not the most outgoing person. Just be genuine!
  • Sit up straight , but don’t be too stiff. Push your back against the back of the seat and don’t just sit on the edge of the chair.
  • Make eye contact , but don’t stare, either.
  • Speak in a clear , calm, and unrushed manner. Don't mumble or whisper, but equally don't shout. Think before you speak!

13. When in doubt, reschedule 

If you’re not feeling confident about your chances, don’t hesitate to reschedule. If you take this course of action, take a few things into consideration. Make sure to suggest an alternative day and avoid rescheduling multiple times at all costs. The consultancy will be grateful for you to suggest an immediate alternative. Try to be transparent as to why you are rescheduling without going too deeply into details. However, rescheduling should only be used as a last resort.

To become the best, you must learn from the best. That is exactly what PrepLounge can offer you. The vast  PrepLounge community  makes it easy to  find case partners with the same ambitions and goals as you. Whether you are looking for a  professional case coach  or other aspiring consultants, you will have no problem finding case partners in the build-up to your interview. Our PrepLounge coaches – from Bain to McKinsey – are uniquely qualified to provide you with insights into the mastery of a case interview.

Apart from case partners from every imaginable background, PrepLounge provides a colossal collection of online resources to give you the best preparation leading up to your case interview. We will provide you with questions and answers to the most important consulting case types and share in-depth knowledge for the best possible case interview preparation. You will be able to find case partners to practice online and always be on top of the latest insights and news regarding consulting jobs and top consulting firms.

As a PrepLounge member, you will receive access to all these perks. PrepLounge will accompany you all the way from your application through to your contract negotiation. You strongly diminish your chance of success without sufficient preparation. Invest in your future and give yourself the best chance at acing your case interview! Exchange your experience with peers from all around the world in our  Consulting Q&A . Join our case interview community today and embark on your journey into consulting!

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Oliver Wyman Case: Full Electrons Ahead

Simon-Kucher & Partners

Simon-Kucher Case: GST Cruise Company


Deloitte Case: Footloose

Oliver wyman case: setting up a wine cellar.

zeb Consulting

zeb case: Quo vadis, customer?

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The Most Common Pitfalls in Case Interview Preparation

The Most Common Pitfalls in Case Interview Preparation

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Consulting Interview Questions – Example Questions and Answers for Your Interview in Management Consulting

Consulting Interview Questions

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McKinsey PEI (Personal Experience Interview)

McKinsey PEI (Personal Experience Interview)

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47 case interview examples (from McKinsey, BCG, Bain, etc.)

Case interview examples - McKinsey, BCG, Bain, etc.

One of the best ways to prepare for   case interviews  at firms like McKinsey, BCG, or Bain, is by studying case interview examples. 

There are a lot of free sample cases out there, but it's really hard to know where to start. So in this article, we have listed all the best free case examples available, in one place.

The below list of resources includes interactive case interview samples provided by consulting firms, video case interview demonstrations, case books, and materials developed by the team here at IGotAnOffer. Let's continue to the list.

  • McKinsey examples
  • BCG examples
  • Bain examples
  • Deloitte examples
  • Other firms' examples
  • Case books from consulting clubs
  • Case interview preparation

Click here to practise 1-on-1 with MBB ex-interviewers

1. mckinsey case interview examples.

  • Beautify case interview (McKinsey website)
  • Diconsa case interview (McKinsey website)
  • Electro-light case interview (McKinsey website)
  • GlobaPharm case interview (McKinsey website)
  • National Education case interview (McKinsey website)
  • Talbot Trucks case interview (McKinsey website)
  • Shops Corporation case interview (McKinsey website)
  • Conservation Forever case interview (McKinsey website)
  • McKinsey case interview guide (by IGotAnOffer)
  • McKinsey live case interview extract (by IGotAnOffer) - See below

2. BCG case interview examples

  • Foods Inc and GenCo case samples  (BCG website)
  • Chateau Boomerang written case interview  (BCG website)
  • BCG case interview guide (by IGotAnOffer)
  • Written cases guide (by IGotAnOffer)
  • BCG live case interview with notes (by IGotAnOffer)
  • BCG mock case interview with ex-BCG associate director - Public sector case (by IGotAnOffer)
  • BCG mock case interview: Revenue problem case (by IGotAnOffer) - See below

3. Bain case interview examples

  • CoffeeCo practice case (Bain website)
  • FashionCo practice case (Bain website)
  • Associate Consultant mock interview video (Bain website)
  • Consultant mock interview video (Bain website)
  • Written case interview tips (Bain website)
  • Bain case interview guide   (by IGotAnOffer)
  • Bain case mock interview with ex-Bain manager (below)

4. Deloitte case interview examples

  • Engagement Strategy practice case (Deloitte website)
  • Recreation Unlimited practice case (Deloitte website)
  • Strategic Vision practice case (Deloitte website)
  • Retail Strategy practice case  (Deloitte website)
  • Finance Strategy practice case  (Deloitte website)
  • Talent Management practice case (Deloitte website)
  • Enterprise Resource Management practice case (Deloitte website)
  • Footloose written case  (by Deloitte)
  • Deloitte case interview guide (by IGotAnOffer)

5. Accenture case interview examples

  • Case interview workbook (by Accenture)
  • Accenture case interview guide (by IGotAnOffer)

6. OC&C case interview examples

  • Leisure Club case example (by OC&C)
  • Imported Spirits case example (by OC&C)

7. Oliver Wyman case interview examples

  • Wumbleworld case sample (Oliver Wyman website)
  • Aqualine case sample (Oliver Wyman website)
  • Oliver Wyman case interview guide (by IGotAnOffer)

8. A.T. Kearney case interview examples

  • Promotion planning case question (A.T. Kearney website)
  • Consulting case book and examples (by A.T. Kearney)
  • AT Kearney case interview guide (by IGotAnOffer)

9. Strategy& / PWC case interview examples

  • Presentation overview with sample questions (by Strategy& / PWC)
  • Strategy& / PWC case interview guide (by IGotAnOffer)

10. L.E.K. Consulting case interview examples

  • Case interview example video walkthrough   (L.E.K. website)
  • Market sizing case example video walkthrough  (L.E.K. website)

11. Roland Berger case interview examples

  • Transit oriented development case webinar part 1  (Roland Berger website)
  • Transit oriented development case webinar part 2   (Roland Berger website)
  • 3D printed hip implants case webinar part 1   (Roland Berger website)
  • 3D printed hip implants case webinar part 2   (Roland Berger website)
  • Roland Berger case interview guide   (by IGotAnOffer)

12. Capital One case interview examples

  • Case interview example video walkthrough  (Capital One website)
  • Capital One case interview guide (by IGotAnOffer)

13. Consulting clubs case interview examples

  • Berkeley case book (2006)
  • Columbia case book (2006)
  • Darden case book (2012)
  • Darden case book (2018)
  • Duke case book (2010)
  • Duke case book (2014)
  • ESADE case book (2011)
  • Goizueta case book (2006)
  • Illinois case book (2015)
  • LBS case book (2006)
  • MIT case book (2001)
  • Notre Dame case book (2017)
  • Ross case book (2010)
  • Wharton case book (2010)

Practice with experts

Using case interview examples is a key part of your interview preparation, but it isn’t enough.

At some point you’ll want to practise with friends or family who can give some useful feedback. However, if you really want the best possible preparation for your case interview, you'll also want to work with ex-consultants who have experience running interviews at McKinsey, Bain, BCG, etc.

If you know anyone who fits that description, fantastic! But for most of us, it's tough to find the right connections to make this happen. And it might also be difficult to practice multiple hours with that person unless you know them really well.

Here's the good news. We've already made the connections for you. We’ve created a coaching service where you can do mock case interviews 1-on-1 with ex-interviewers from MBB firms . Start scheduling sessions today!

The IGotAnOffer team

Interview coach and candidate conduct a video call

Case Interview Math - Know THIS Before Your Consulting Interview

  • Last Updated January, 2024

Rebecca Smith-Allen

Former McKinsey Engagement Manager

Why is Case Math Important?

Steps to Minimize Mistakes

4 Types of Case Math Problems

Extracting Data From Charts

Case Math Examples

Critical Numbers to Know

Market Sizing Math

Links to Resources

Are you nervous about solving math problems in the middle of your consulting interview? 

Don’t worry. You’re not alone. 

Luckily, typical case interview math problems aren’t hard. They’re basic algebra – addition, subtraction, multiplication, division, and fractions/percentages. They can also involve extracting data from tables and interpreting it. All the math you need you covered by age 13–and if you need to brush up, we’ve got you covered.

You’ll find consulting math easier if you know what type of problems to expect and follow our 4-step approach to minimizing case interview math mistakes . 

If this is your first visit to MyConsultingOffer.org – head to  Case Interview Prep   for an intro to the management consulting interview process. 

If you’re familiar with what a consulting case interview is, and want a preview of the math you’ll need to succeed in consulting interviews, you’re in the right place. 

Let’s get started!

Why Do Consulting Case Interviewers Care about Math Skills When Everyone Has a Calculator in their Phone?

Why do case math because a consulting team’s time is expensive..

Nail the case & fit interview with strategies from former MBB Interviewers that have helped 89.6% of our clients pass the case interview.

Consulting Math: 4 Types of Problems

1. market sizing.

Examples: What is the size of the market for laundry detergent in Latin America? How many pizza pies are consumed each day in Pittsburgh?

2. Financial calculations

Examples: What are XYZ company’s profits? What is XYZ company’s profit margin? What is XYZ company’s market share? What is XYZ company’s growth rate?

3. Investment analysis

Example: How many years would it take to break-even on an investment? What is the return on investment?

4. Operations problems

Example: What is the capacity (of a factory, machine or worker)? What is the utilization rate?

Watch this video to learn how to master case interview math. For reference, I’ll also provide key formulas and examples below.

Case Interview Math Examples

Financial calculations.

Here are the key formulas you need to know:

  • Profits = Revenue – Costs
  • Profit margin = Profits/Revenue
  • Market share = Revenue for XYZ company/Revenue for all companies in the market
  • Growth rate = (New –  Old) /Old 

So Revenue growth rate = ( this year’s revenue – last year’s revenue) / last year’s revenue

Here are some examples of financial math calculations:

  • A firm with $100 million in revenue and $80 million in costs has profits of $20 million.
  • A firm with $20 million in profits and $100 million in revenue has a 20% profit margin.
  • A firm with $100 million in revenue in an industry with $400 million revenues has a 25% market share.
  • A firm that made $100 million this year and $90 million last year had an 11% growth rate.

Investment Analysis

  • Break-even:  Investment cost / annual profit = years to break even
  • Return on investment (ROI) = (Revenue – investment costs) / Investment cost

Here are some examples of investment calculations:

  • A company spends $10 million in costs to enter a business with annual profits of $1 million has a 10-year payback.
  • A company that will earn  $12 million on a business that it paid $10 million to enter had a 20% ROI.

Operations Problems

  • Capacity in units = total capacity / capacity required to make one unit 
  • Utilization rate = actual output / maximum possible output

Here are some examples of operations math calculations:

  • If a machine that can produce a widget every 5 minutes, it has a capacity of producing 96 widgets in an 8-hour shift. 8 hours * (60 minutes/hour) / 5 minutes = 96.
  • If the widget machine is left unmanned while the operator is at lunch (1 hour) and during breaks (2, 15 minutes each), then the machine will only make 78 widgets. 78 widgets / its capacity of 96 means it ran at a utilization rate of 81.25%.

My friend attended college with me. She was a non-American student and I knew she wanted to marry someone who could give her American citizenship, so I started with the US population – 320 million .

Then I cut the population in half to focus on men since she was interested only in men. 320 million / 2 = 160 million.

To rule out men who were too old or too young for her, I cut the population of men into age groups. The average life expectancy in the U.S. is 80 years. I wanted to focus on only men 20-30, so 1/8 of the U.S. male population. 160 million / 8 = 20 million.

I also wanted to focus on men that were taller than her, but actually, my friend is pretty short. Almost all men in the right age range are taller than her so there was no need to factor that into my calculation. Men 20-30 who are taller than Davis’s very short friend = 100% or 20 million.

Next, I looked at attractiveness: both the portion of the target male population that my friend would find attractive and the percentage of those guys who would find her attractive. 

This friend’s pretty picky. She was only interested in guys who were 9’s or 10’s on a scale of 1 to 10, so about 20% of the population. 20 million men aged 20-30 * 20% who are really hot = 4 million.

I decided to be conservative and assume only 10% of the population my friend thought was attractive would also find her attractive. 10 % of the 4 million hot guys age 20-30 would find her attractive = 400,000.

My friend wanted a guy that had a good income, so I decided to focus on people attending or who’d graduated from college. In fact, she was really picky, so I decided to focus on top colleges like the Ivy League schools. About 1% of the U.S. male population attends highly competitive schools like the Ivy League. 400,000 * 1% = 4,000.

Finally, I assumed many of the guys who were in the right age range and who my friend found attractive and who found her attractive and who went to a top college might already be taken. I cut the number I’d come up with in half to reflect the highly eligible guys who were already off the market. 4,000 hot, really smart guys age 20-30 / 2 = 2,000.

My “so what” based on this analysis was that my friend might want to be a little less picky. All her requirements brought the number of eligible bachelors down from 160 million to only 2,000. But she thought that a group of 2,000 guys was plenty for her to find Mr. Right in, so she decided to keep her standards high.

4 Steps to Minimizing Mistakes in Case Interview Math

It’s hard to do math under the pressure of an interview. These steps are the key to keeping your math accurate.

1 – Be clear on what the calculation will tell you.

Don’t just start doing calculations. Know what business problem you’re trying to solve and how your math will give you insight so you can make a decision. Share this with your interviewer.

2 – Structure your approach.

Before you do any calculation, walk through the steps you’ll take to answer the question with your interviewer. There are frequently several steps in consulting math problems.

3 – Do the calculation step-by-step.

Once you have your approach to the case math problem, do one calculation at a time to ensure accuracy.

4 – Explain the “so what?”

Don’t wrap up your answer with just a number, explain what the number means in the context of the business problem you were trying to solve. What would you recommend to the client?

Here’s an example of Consulting Math:

A manufacturer of high-quality wood outdoor furniture is considering extending its product line to include Adirondack chairs. It only wants to enter the market if it can make at least $5 million a year.

Data provided: 

The size of the North America market for Adirondack chairs is estimated to be $1 billion. The top 4 players hold 20% market share between them. Profit margins average 20%. 

Now apply the 4-step approach for minimizing mistakes.

Be clear on what the calculation will tell you. “I’d like to calculate likely market share and profit our client could expect if it entered the market for Adirondack chairs in order to see if the opportunity is large enough to meet their criteria of $5 million profits.”

Structure your approach. “ To do this calculation, I’d first look at the likely market share our client could achieve based on the share of the top 4 players in the market. Then I’d calculate the revenues that they could expect by multiplying the market share by the size of the market. I’d then use the industry’s average profit margin to calculate the level of profit they could expect.”

Do the calculation step-by-step. “ The top 4 players in the market for Adirondack chairs have a combined market share of 20%. 20% market share /4 players = an average market share of 5%. Based on the client’s success in the wood outdoor furniture market, we expect they could achieve this level of market share as well.”A 5% market share in a market with $1 billion in annual revenue would give the client $1 billion * .05 or $50 million in revenue.$50 million in revenue for a product with a 20% profit margin would give the client $10 million in expected revenue.”

Explain the “So what?” “ Based on these calculations, the client should consider entering the market for Adirondack chairs because the expected annual revenue of $10 million exceeds their minimum criteria of $5 million.”

More case interview math: extracting data from charts.

In some cases, particularly when a case interview math problem is one step in a multi-step case question, an interviewer might hand you a chart with key information on it. These charts often have more pieces of data on them than you need. You need to find the right data. Or, you may need to manipulate the data to find what you need.

For example, a table might provide a company’s costs and revenues when the information you need is profit margin. Or, it might provide the revenues of the top 4 companies in the market and a 5th number that totals the revenue of all other players in the market, but you might need market share for player #3.

Don’t let all the number on the chart throw you. You’ll still be using the same basic formulas to analyze these numbers. 

Instead, take a minute to understand the information the chart provides and explain it to your interviewer. Then proceed with the case interview math problem as described above: be clear about what you’re looking for in the calculation, walk the interviewer through your approach, do the actual calculation, and then provide the “so what.” Using this approach will make interpreting data tables in an interview straightforward.

Critical Numbers to Know for Case Math Problems

Links to bain, bcg & mckinsey resources on case interview math.

Want to hear more about the importance of case interview math straight from the top management consulting firms? Bain and BCG list quantitative analysis as part of what they test for. McKinsey provides examples of the type case math in its case interviews in this practice test .

On this page, we’ve covered the typical types of case interview math problems you’ll see, explained how to extract data from charts, and provided tips on minimizing your consulting math mistakes. These skills will help boost your confidence in management consulting interviews and ensure you ace your case.

People who are working on their consulting math skills typically find the following other pages helpful:

  • MECE – Mutually Exclusive, Collectively Exhausting ,
  • McKinsey Case Interview,  and
  • Consulting Written Case Interviews .

We hope this page has increased your confidence in tackling consulting math problems! Comment below on the types of consulting math problems you find the toughest. We’ll provide tips from our coaches.

Help with Case Study Interview Preparation

Thanks for turning to My Consulting Offer for advice on case study interview prep. My Consulting Offer has helped almost 85% of the people we’ve worked with to get a job in management consulting.  For example, here is how Brenda was able to get a BCG offer when she only had 1 week to prepare…

We want you to be successful in your consulting interviews too.

If you want to learn more about how to ace your case interviews, apply to work with us.  We’ll show you how you get an offer without spending hundreds of hours preparing.

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    So in this article, we have listed all the best free case examples available, in one place. The below list of resources includes interactive case interview samples provided by consulting firms, video case interview demonstrations, case books, and materials developed by the team here at IGotAnOffer. Let's continue to the list. McKinsey examples

  23. Consulting Case Interview Math Practice

    You're not alone. Luckily, typical case interview math problems aren't hard. They're basic algebra - addition, subtraction, multiplication, division, and fractions/percentages. They can also involve extracting data from tables and interpreting it. All the math you need you covered by age 13-and if you need to brush up, we've got you ...