Case Interview Examples & Sample Cases

A case interview is a short business problem you solve out loud with the interviewer. You will hear a prompt, structure your approach, ask for data, run some quick arithmetic, and finish with a recommendation. Most cases at McKinsey, BCG, and Bain fall into a few recognizable shapes. Below is one sample case interview for each of the four most common types, written so you can see the reasoning, not just the answer. Treat these as case interview questions and answers to study, then go practice fresh ones.

A profitability case example (and how to structure it)

Prompt. "Our client is a regional coffee-shop chain. Over the past year, profits have dropped about 20% even though store count is flat. Why, and what should they do?"

The first move is not to guess. It is to lay out the equation that governs every profitability case:

• Profit = Revenue − Cost.
• Revenue = Price × Quantity (here, average ticket × number of transactions).
• Cost = Fixed costs + Variable costs (rent and salaried staff vs. coffee, milk, cups, hourly labor).

Then you isolate the problem before drilling down. Ask: "Has the drop come from falling revenue, rising cost, or both?" That single question turns a vague prompt into a directed investigation. Suppose the data shows revenue is roughly flat but costs are up. You have just halved the search space — now you work the cost branch.

The math. Say each store made $500,000 in revenue with a 20% profit margin last year, so $100,000 profit. A 20% profit drop is $20,000 per store. If revenue held and that $20,000 is pure cost increase, you are looking for roughly a 4% rise in total costs ($20,000 on $400,000 of cost). Now you can test candidates: did the milk supplier raise prices? Did a minimum-wage change lift hourly labor? Is one new lease dragging the average?

The recommendation. If the culprit is variable input cost, options include renegotiating supply, adjusting portion sizes, or a modest price increase to protect margin. Close with a clear "I'd recommend X, because it recovers the most margin with the least risk to volume," plus the one risk you would watch. For the full breakdown of this template, see our case interview frameworks guide.

A market-entry case example

Prompt. "A large European grocery retailer is considering entering the meal-kit delivery market. Should they?"

Market-entry cases reward a structure that separates "is this market worth entering?" from "can this client win in it?" A clean structure has four buckets:

1. The market. How big is it, how fast is it growing, and how profitable is it? (This is where you'll do a quick market-sizing — see the next section.)
2. Competition. Who already serves it, how concentrated is it, and is there room for another player?
3. The client's right to win. What assets does the grocer have — supply chain, brand, customer base — that a pure startup lacks?
4. Entry economics & route in. Build, buy, or partner? What's the investment and the breakeven?

The judgment. The trap is to decide on market size alone. A $2B growing market is useless if three incumbents own it and the client has no edge. The strong answer ties the buckets together: "The market is attractive and growing, and the client's cold-chain logistics and 8 million loyalty members give it a genuine right to win, so I'd recommend entering — but via partnership first to limit downside." That last clause shows you weighed risk.

An M&A / acquisition case example

Prompt. "A private-equity firm is considering acquiring a mid-sized software company. Should they buy it, and at what kind of price?"

An acquisition case is a market-entry case with valuation bolted on. Structure it around four questions:

1. Rationale. Why buy at all? Growth, a capability, market access, or cost synergies? A deal without a clear reason is a red flag.
2. The target on its own. Is the standalone business healthy — growing revenue, defensible margins, real customers? Run a mini profitability read here.
3. Synergies. What value appears only after the deal — cross-sell, removed duplicate costs, pricing power? Be specific and skeptical; synergies are routinely overstated.
4. Price & returns. Does the expected value exceed the price? A simple frame: standalone value + synergies − integration cost, compared with the asking price.

The math you might be asked. If the target earns $30M a year and comparable software companies trade at roughly 10× earnings, a first-pass valuation is about $300M. If credible synergies add $5M a year of recurring profit, that's another ~$50M of value at the same multiple — so paying up to ~$350M could still make sense, while $450M would need a much stronger story. Showing that arithmetic, then sanity-checking it, is exactly the business insight interviewers score.

The recommendation. Land on buy / don't buy / buy-below-X, naming the single assumption your answer hinges on (usually the synergy estimate) and how you'd pressure-test it in diligence.

A market-sizing example

Market-sizing (or "guesstimate") questions show up on their own and inside larger cases. The interviewer isn't checking whether you know the real number — they're watching how you build an estimate from sensible assumptions and clean arithmetic.

Prompt. "How many cups of coffee are sold by cafes in a city of 5 million people each day?"

Work top-down, stating each assumption out loud:

• Population: 5,000,000.
• Share who buy a cafe coffee on a given day: assume ~30% → 1,500,000 people.
• Average cups per coffee-buyer per day: assume 1.3 → ~1,950,000 cups.
• Round to a clean estimate: roughly 2 million cups a day.

Then do two things that separate strong candidates. First, sanity-check: 2 million cups across, say, 2,000 cafes is ~1,000 cups per cafe per day — high but plausible for a dense city, lower if you assumed fewer outlets. Second, name what would move the answer most — here, the 30% participation rate. Flagging your biggest lever shows the quantitative judgment interviewers reward. For more of these, see our case interview questions bank.

How to use examples without memorizing answers

Here is the mistake that sinks prepared candidates: they memorize a worked case and try to replay it. Interviewers notice immediately. They tweak a number, swap an industry, or ask "what else?" and the memorized script falls apart, because there was never any real reasoning underneath it.

Worked examples are valuable for a different reason — they show you the moves a strong candidate makes:

• Translating a vague prompt into a clean structure before touching any data.
• Isolating where the problem lives before drilling down (revenue vs. cost, market vs. right-to-win).
• Choosing what to calculate, then sanity-checking the result instead of trusting it blindly.
• Tying the analysis back to a recommendation with a named risk.

So read each example for the thinking, not the answer. Then close the page and do a fresh case out loud — different industry, different numbers. Reading about cases builds recognition; speaking through them builds the skill the interview actually tests. A live, spoken rep also surfaces the gaps silent reading hides: filler words, math that falls apart under time pressure, structures that sound neat in your head but ramble when you say them.

That out-loud practice is exactly what AI Mock Case is built for. You run a full live voice interview with an AI interviewer that interrupts and pushes back, then minutes later you get a five-dimension scorecard (Structure, Quantitative, Business Insight, Communication, Recommendation) emailed to you — each score tied to what you actually said. It was built by two ex-MBB interviewers with 5+ years coaching behind a 100+ case library, and it's currently in private beta.

Keep going

Pair these examples with the rest of the practice library: