Author: Taylor Warfield, Former Bain Manager and interviewer

Last Updated: June 15, 2026

 

This case interview cheat sheet gives you the frameworks, formulas, mental math shortcuts, and word-for-word scripts you need to solve any consulting case at McKinsey, BCG, or Bain. Keep reading for a complete study plan, the six most common case types, and the exact phrases top candidates use at every step of a case.

 

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Key Takeaways

 

A case interview cheat sheet condenses the frameworks, formulas, and strategies you need to pass consulting interviews into a single reference you can review before any case.

 

• Every case follows the same seven steps, from understanding the background to delivering a recommendation

 

• Six framework types cover the large majority of first round cases: profitability, market entry, M&A, pricing, growth strategy, and new product

 

• You need 12 core formulas memorized cold because calculators are not allowed

 

• Custom frameworks beat memorized ones, and interviewers are trained to spot the difference

 

• Most candidates who land offers invest 50 to 80 hours of preparation over 4 to 8 weeks

 

What Changed in 2026?

 

This update adds a word-for-word script for every step of the case, an expanded breakdown of all five case interview formats, and a fraction to percentage conversion table for faster math. Reference numbers like U.S. median household income have also been refreshed with the latest Census Bureau data.

 

Where Can You Download a Case Interview Cheat Sheet?

 

Download our Case Interview Cheat Sheet and Study Guide, which covers all of the most important things you need to know. If you prefer to read the case interview cheat sheet in plain text, the full content is below.

 

What Is a Case Interview?

 

A case interview is a 30 to 45 minute exercise where you solve a hypothetical business problem alongside the interviewer. You structure the problem, analyze data, perform calculations without a calculator, and deliver a recommendation. Consulting firms use case interviews to simulate the actual work consultants do on client projects.

 

You will be given a scenario like "How can a retailer increase profits?" or "Should a tech company enter a new market?" BCG's case interview preparation page emphasizes that there is not always a single right answer and that the quality of your reasoning matters most.

 

What are the different types of case interviews?

 

There are five formats you can encounter, and the split between candidate-led and interviewer-led case interviews shapes how you should practice. Here is what each format involves.

 

• Candidate-led case: you drive the direction of the case, choosing which areas to explore and what analysis to do. This is the most common format at BCG and Bain

 

• Interviewer-led case: the interviewer steers the conversation and asks you specific questions in a set order. McKinsey primarily uses this format

 

• Market sizing: standalone estimation questions like "How many smartphones are sold in the U.S. each year?" Many firms use market sizing as a quick screen of your quantitative reasoning

 

• Written case: you receive a packet of data, analyze it on your own, and present recommendations. Firms like Deloitte and Bain use written case interviews in some offices and rounds

 

• Group case: you solve a case with other candidates while interviewers observe how you collaborate. Group case interviews are less common but appear at firms like EY-Parthenon

 

What Does a Case Interview Assess?

 

In my experience interviewing candidates at Bain, we evaluated five things. Every consulting firm looks for these same qualities, regardless of the case format.

 

Skill	What interviewers look for
Structured thinking	Can you break a messy problem into clear, organized parts?
Analytical problem solving	Can you interpret data, spot patterns, and draw the right conclusions?
Business acumen	Do you understand how businesses make money and the key drivers behind decisions?
Communication	Can you explain your thinking clearly and concisely under pressure?
Personality and cultural fit	Would your interviewer want to work with you on a client project?

 

The typical consulting interview process includes 2 rounds with 2 to 3 case interviews per round. Candidates who score well across all five dimensions in every interview are the ones who receive offers.

 

What Are the Steps in a Case Interview?

 

Every case interview follows the same seven steps, regardless of the firm or format. Having coached hundreds of candidates, I can tell you that the people who internalize this structure perform significantly better than those who try to wing it.

 

1. Understand the case background: take notes while the interviewer reads the case information. Pay close attention to the company, the context, and the specific objective
   
   
2. Ask clarifying questions: ask 1 to 3 questions to confirm the objective, understand the company, or define an unfamiliar term
   
   
3. Structure a framework: break the problem into 3 to 4 major areas that together cover everything that matters
   
   
4. Start the case: in a candidate-led case, propose which area to explore first. In an interviewer-led case, the interviewer tells you where to start
   
   
5. Solve quantitative problems: expect estimation questions, profitability or breakeven calculations, and exhibits to interpret
   
   
6. Answer qualitative questions: these include brainstorming questions and business judgment questions
   
   
7. Deliver a recommendation: state your recommendation, give 2 to 3 supporting reasons, and suggest next steps

 

What Should You Say at Each Step of a Case Interview?

 

Most cheat sheets tell you what to do but not what to say. As a Bain interviewer, I could tell within the first two minutes whether a candidate had practiced speaking out loud, so memorize these phrases until they feel natural.

 

Use the first script immediately after the prompt, before you ask any clarifying questions. It confirms you are solving the right problem.

 

Moment in the case	What to say
Recapping the prompt	"Just to confirm, our client is [company], and our objective is to [objective]. Is that right?"
Asking for time	"Could I take about a minute to structure my thoughts?"
Presenting your framework	"I'd like to look at four areas. First, [bucket]. Second, [bucket]..."
Transitioning between areas	"We've learned [insight]. Next, I'd like to explore [area] because [reason]."
Before doing math	"Let me walk you through my approach before I calculate."
After a calculation	"That gives us [number], which means [implication] for our client."
Asking for data	"To size this, I would need [data point]. Do we have that information?"
Opening your recommendation	"I recommend our client [action] for three reasons."

 

Notice that every script is short and answer-first. Interviewers reward candidates who lead with the conclusion and then explain, which is exactly how consultants present to clients.

 

How Do You Build a Custom Framework?

 

The biggest mistake candidates make is memorizing rigid frameworks and applying them to every case. Interviewers at McKinsey, BCG, and Bain can immediately tell when you are reciting a memorized structure, and it will hurt your evaluation.

 

Instead, build a custom framework for every case by asking yourself: "What 3 to 4 things must be true for me to confidently make a recommendation?" Those become your buckets, and the structure must be MECE, meaning the parts do not overlap and nothing important is missing.

 

For example, if a company is considering entering the organic snack market, you might decide these four things need to be true:

 

• The organic snack market is large and growing

 

• Competition is manageable and the company can differentiate

 

• The company has the capabilities to produce and distribute the product

 

• The company will earn attractive profits from entering

 

Those four areas become your framework. Under each one, add 2 to 3 specific questions you need answered. This process takes about 60 seconds and produces a structure that is tailored to the specific case.

 

What are the most common case interview frameworks?

 

While you should never apply them word for word, these six case interview frameworks give you building blocks to draw from. In my experience interviewing at Bain, the large majority of first round cases fall into one of these categories.

 

Case type	Core question	Key framework areas
Profitability	Why are profits declining?	Revenue breakdown, cost breakdown, customer trends, competitor moves
Market entry	Should the company enter this market?	Market attractiveness, competition, capabilities, expected profitability
Merger & acquisition	Should the company acquire this target?	Market attractiveness, target quality, synergies, financial return
Pricing	How should the company price this product?	Cost-based floor, value-based ceiling, competitive benchmarking
Growth strategy	How should the company grow?	Organic vs. inorganic, new products, new markets, new customers
New product	Should the company launch this product?	Target segment, customer needs, capabilities, profitability

 

If you want to learn case interviews quickly, my case interview course walks you through proven framework strategies for each case type. You can build sharp frameworks in under 60 seconds after completing the course.

 

What Formulas Do You Need for Case Interviews?

 

You will not have a calculator in your interview, so you need these 12 case interview formulas memorized cold. In my experience, candidates who know them solve quantitative problems roughly twice as fast as those who try to figure them out on the spot.

 

Profit formulas

 

• Profit = Revenue - Costs

 

• Revenue = Quantity × Price

 

• Costs = Total Variable Costs + Total Fixed Costs

 

• Total Variable Costs = Quantity × Variable Cost per Unit

 

• Profit Margin = (Profit ÷ Revenue) × 100

 

Investment formulas

 

• Return on Investment (ROI) = Profit ÷ Investment Cost

 

• Payback Period = Investment Cost ÷ Annual Profit

 

• Net Present Value (perpetuity) = Annual Cash Flow ÷ Discount Rate

 

Operations and market formulas

 

• Break-even Point (units) = Fixed Costs ÷ (Price - Variable Cost per Unit)

 

• Market Share = Company Revenue ÷ Total Market Revenue

 

• Contribution Margin = Price - Variable Cost per Unit

 

• CAGR = (Ending Value ÷ Beginning Value)^(1 ÷ Number of Years) - 1

 

The break-even formula deserves extra attention because breakeven analysis appears in market entry, new product, and investment cases alike. Here's an example: if a coffee shop has $10,000 in monthly fixed costs, sells each cup for $5, and pays $2 in variable costs per cup, it must sell $10,000 ÷ $3 = roughly 3,333 cups to break even.

 

What Mental Math Shortcuts Should You Know?

 

Speed matters in case interviews. You typically have 30 to 40 minutes total, and spending 5 minutes on a calculation that should take 30 seconds will cost you.

 

Shortcut	How it works	Example
Multiply by 5	Divide by 2, then multiply by 10	840 × 5 = 420 × 10 = 4,200
Calculate percentages	Combine 10% and 5% building blocks	15% of 6,400 = 640 + 320 = 960
Rule of 72	72 ÷ growth rate = years to double	8% growth doubles in ~9 years
Divide by 8	Halve the number three times	4,800 ÷ 8 = 2,400 → 1,200 → 600
Round and adjust	Round to easy numbers, then correct	49 × 32 = (50 × 32) - 32 = 1,568
Break apart multiplications	Split into parts and add	370 × 24 = (370 × 20) + (370 × 4) = 8,880

 

You should also memorize the fraction to percentage conversions below. Converting a division problem into a familiar fraction is often the fastest path to an answer.

 

Fraction	Percentage	Fraction	Percentage
1/2	50%	1/7	~14%
1/3	~33%	1/8	12.5%
1/4	25%	1/9	~11%
1/5	20%	1/10	10%
1/6	~17%	1/12	~8%

 

Practice case interview math for 15 minutes a day for two weeks until these shortcuts become automatic. Your interviewer should see smooth, confident calculations with no long pauses.

 

How Should You Take Notes During a Case?

 

Good note-taking is one of the most underrated skills in case interviews. Having coached hundreds of candidates, I have seen more people lose track of their case because of messy notes than because of poor analytical skills.

 

Use this three-sheet system:

 

• Sheet 1 (Main sheet): turn your paper sideways so it is wider than it is tall. Write the company name and objective at the top and draw your framework below. Every time you finish a section, write the key takeaway next to the relevant framework bucket

 

• Sheet 2 (Math sheet): do all calculations on a separate sheet. Label each calculation and show your work clearly so the interviewer can follow along

 

• Sheet 3+ (Data sheets): use additional sheets for any data, charts, or exhibits the interviewer provides. Number your pages so you can quickly reference earlier data

 

At the end of the case, your main sheet should hold a clear summary of findings that makes it easy to deliver a structured recommendation.

 

What Numbers Should You Memorize for Case Interviews?

 

Most case interviews do not require specialized knowledge, but a few memorized reference numbers help you make faster, more credible assumptions in estimation questions.

 

General statistics

 

• Global population: 8 billion

 

• Average U.S. household size: 2.5 people

 

• Average life expectancy: 80 years

 

• U.S. median household income: roughly $84,000, based on the Census Bureau's 2024 income report

 

Country populations

 

Country	Population	Country	Population
United States	335 million	Germany	84 million
China	1.4 billion	United Kingdom	68 million
India	1.4 billion	France	68 million
Brazil	215 million	Canada	40 million
Japan	125 million	Australia	26 million
Mexico	130 million	Russia	145 million

 

What Are the Most Common Case Interview Mistakes?

 

After interviewing and coaching hundreds of consulting candidates, I can tell you that most people fail their cases for the same handful of reasons. Avoid these six mistakes and you will already outperform the majority of candidates.

 

1. Reciting a memorized framework: interviewers at McKinsey, BCG, and Bain are trained to spot this. Build a custom framework for every case
   
   
2. Jumping into math before structuring: always lay out your approach before doing any calculations. This prevents you from solving the wrong problem
   
   
3. Doing math silently: talk through your calculations out loud so the interviewer can follow your logic and correct small mistakes before they snowball
   
   
4. Forgetting to sanity check your answer: if your calculation says a coffee shop earns $50 million a year, something is clearly wrong. Always check your answer against common sense
   
   
5. Not connecting answers to the objective: after every question, explain what the finding means for the overall recommendation. Never state a number without context
   
   
6. Giving a wishy-washy recommendation: pick one recommendation and commit to it. Do not hedge by saying "it depends"

 

What Are the Best Case Interview Tips?

 

The case interview tips below come from my time interviewing candidates at Bain and coaching hundreds more through their preparation. Each one addresses a specific skill that interviewers evaluate.

 

Tip #1: Confirm the objective before doing anything else

 

Solving the wrong problem is the fastest way to fail a case. Restate the question in your own words and get explicit confirmation before you build anything.

 

Tip #2: Use the first 60 seconds wisely

 

Ask for a moment of silence to build your framework. Interviewers expect this and will not penalize you for taking time to think.

 

Tip #3: Structure every qualitative answer

 

When brainstorming, use a simple two-part structure like internal/external, short-term/long-term, or economic/non-economic. This shows organized thinking even on open-ended questions.

 

Tip #4: Always say "so what?"

 

After every data point or calculation, explain what it means for the case. This habit is what separates average candidates from great ones.

 

Tip #5: Be 80/20

 

Focus on the 20% of questions that drive 80% of the answer. Do not try to explore every single issue. Prioritize ruthlessly.

 

Tip #6: Ask for data instead of assuming

 

Do not make assumptions when the interviewer has actual data to share. Frame your request clearly: "To size this opportunity, I would need average revenue per customer. Do you have that data?"

 

Tip #7: Lead with the headline when reading exhibits

 

When you receive charts and graphs, state the single most important insight in one sentence before describing details. Interviewers care about the takeaway, not a tour of the axes.

 

Tip #8: Show your personality

 

Interviewers want to hire someone they would enjoy working with on a long client project. Be professional but also be yourself.

 

Tip #9: Practice with a timer

 

Real cases have strict time limits. Practice completing a full case in 30 to 35 minutes so you never feel rushed on the day.

 

How Should You Deliver Your Final Recommendation?

 

Your closing recommendation is the most important 60 seconds of the entire interview. Use this three-part structure that mirrors how real consultants present to clients.

 

1. State your recommendation clearly: "I recommend that [Company] should [action]"
   
   
2. Provide 2 to 3 supporting reasons: "Three findings support this. First, [reason]. Second, [reason]. Third, [reason]"
   
   
3. Suggest next steps: "If I had more time, I would want to investigate [area] to further validate this recommendation"

 

Here's an example with illustrative numbers. Let's say the case asked whether a coffee chain should launch a delivery service.

 

"I recommend the client launch the delivery service. Three findings support this. First, the addressable delivery market is roughly $50 million and growing. Second, the service breaks even at 2,000 orders per week, well below projected demand of 5,000. Third, no major competitor offers delivery in the client's core cities. If I had more time, I would pressure test the delivery cost assumptions and pilot the service in two cities first."

 

Keep your total recommendation under 60 seconds. Be direct and confident, and do not introduce new information you have not discussed during the case.

 

How Long Does It Take to Prepare for Case Interviews?

 

Based on the candidates I have coached, most people who land offers at top consulting firms invest 50 to 80 hours of total preparation over 4 to 8 weeks. Here is a realistic study timeline.

 

Week	Focus area	Activities
Week 1	Learn the fundamentals	Study frameworks, formulas, and case structure. Read this cheat sheet. Complete 2 to 3 solo practice cases.
Week 2	Build core skills	Practice mental math daily. Do 3 to 5 cases independently with a focus on structuring and quantitative problems.
Weeks 3 to 4	Practice with partners	Do 5 to 10 live cases with a partner. Focus on communication, timing, and getting feedback after each case.
Weeks 5 to 6	Get expert feedback	Do 2 to 3 cases with a former or current consultant. Work on your specific improvement areas.
Final week	Stay sharp	Do 1 to 2 cases to stay fresh. Do not overdo it. Avoid case fatigue before the real interview.

 

Quality beats quantity at every stage. Working through 20 well-chosen case interview examples with honest feedback will get you further than rushing through 40 without reflection.

 

If you want to accelerate this timeline, my case interview coaching program provides 1-on-1 sessions with personalized feedback so you can improve far faster than practicing on your own.

 

Treat this case interview cheat sheet as your single study reference: review it before every practice session and again the night before your interview. The most important action you can take today is simple. Complete your first practice case out loud.

 

Frequently Asked Questions

 

Can you prepare for a case interview in one week?

 

Yes, but only with focused effort. Prioritize last minute case interview prep essentials: learn the seven steps of a case, memorize the 12 core formulas, and complete 5 to 8 practice cases out loud. One week is tight, so practice every single day and get feedback wherever possible.

 

What is the hardest part of a case interview?

 

For most candidates, building a custom framework under time pressure is the biggest challenge. Having coached hundreds of people through this process, I have found that the candidates who struggle most are those who force-fit memorized frameworks rather than thinking critically about the specific problem in front of them.

 

Do you need a business background to pass case interviews?

 

No. Top consulting firms hire extensively from engineering, humanities, and science backgrounds. You need to learn the business fundamentals covered in this cheat sheet, but you do not need an MBA or a business degree to receive an offer.

 

How many practice cases should you do before your interview?

 

Most candidates who receive offers complete 20 to 40 practice cases. Quality matters more than quantity, so five cases with thorough feedback beat 20 cases rushed through without reflection. You can also practice case interviews by yourself between partner sessions to build extra repetitions.

 

Can you use notes during a case interview?

 

Yes. You are expected to take notes throughout the case. Bring a pen and several sheets of blank paper, and use the three-sheet system described in this cheat sheet to keep your notes organized and easy to reference.

 

Is memorizing frameworks enough to pass a case interview?

 

No. Interviewers at McKinsey, BCG, and Bain are trained to spot memorized frameworks, and reciting one will hurt your evaluation. Use the six framework types in this cheat sheet as building blocks, then create a custom structure tailored to each specific case.

 

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