How to prepare for case interviews: a 4-week plan (2026)

How to prepare for case interviews, in one line: practise solving business problems out loud, live and timed, review every attempt, and drill the parts that break. A case is a short consulting project squeezed into a conversation. The interviewer gives you a client problem ('profit is down 20%, why?'), holds the data, and watches how you structure it, work the numbers, read the exhibits and land a recommendation. Reading about cases does not build that skill. Doing them does. This guide gives you a four-week plan to get there.

At McKinsey, BCG and Bain, and at most firms that recruit the same way, a case usually takes 25 to 35 minutes of a 45 to 60-minute interview that also covers your experience. Firms typically run two rounds with two or three interviews in each, though formats vary by firm, office and year, so confirm the details with your recruiter.

You are scored on how you think, not on finding a secret answer. Two candidates can reach the same recommendation and get opposite results: one built a clear structure, caught their own maths slip and linked every finding back to the client's goal; the other got there by luck. Your preparation should train the first candidate's habits.

Cases come in two broad styles. In interviewer-led cases, more typical of McKinsey, the interviewer sets each question in turn. In candidate-led cases, more typical of BCG and Bain, you decide what to look at next. Treat these as tendencies, not rules, and practise both. The case interview method lesson walks through each phase in detail.

Firms do not publish their scoresheets, but the same areas come up everywhere. Each one is a separate skill with its own drill, which is why doing case after case without targeted practice plateaus so quickly.

Notice what is missing: knowing the right framework. Frameworks are a starting checklist, covered in our guide to case interview frameworks. What gets scored is how you adapt them to the client in front of you.

Maths deserves a special mention because it is the skill candidates most often underrate. The maths itself is simple, but doing it by hand while someone watches is not. Try the question below. You should be able to answer questions like this in under 30 seconds by the end of week 2.

The plan assumes about 1.5 to 2 hours a day, six days a week, with one day off. If you have less time each day, stretch it to six or eight weeks rather than skipping parts. If you have only two weeks, compress weeks 1 and 2 into one and keep weeks 3 and 4.

That adds up to 26 to 29 live cases. The number matters less than the shape: learn the method before you do volume, do volume before you polish, and taper before the real thing.

Week 1: foundations

Learn the method before you practise it. Read the method lesson, then issue trees and MECE, then case maths essentials. Make your first two cases guided: a walkthrough breaks a case into the steps an interviewer would take you through and gives feedback on each answer, so you see what good looks like before anyone is watching. By the end of the week, do your first fully live case. It will feel slow and clumsy. That is what week 1 is for.

Week 2: the case types

Take one case type a day: profitability, market entry, market sizing, pricing, M&A, then operations. For each, read the matching lesson, do two or three framework drills, then a live case of that type. Add exhibit practice this week, because nearly every case includes a chart or table, and reading one quickly is a separate skill from structuring.

Week 3: volume and fluency

This is the week that builds fluency. Do one or two cases a day, alternating between cases with a partner and cases with the AI interviewer. Mix interviewer-led and candidate-led formats. Stop learning new material: from now on, your drills come from your review notes, not from the syllabus.

Week 4: simulate, then taper

Run full mock interviews: a fit question, then a case, twice back to back, the way a real round feels. Fit firm-specific preparation in here too, including any online test you face, such as McKinsey Solve or BCG Casey. In the last three or four days, cut back to one case a day (more on that below).

Short daily drills beat long weekend sessions. Ten minutes of maths every day for four weeks will do more for you than a three-hour cram on a Sunday, because what you are building is speed and confidence, and both come from repetition.

Quality beats count. You will read advice to do 50 or even 100 cases. For most candidates, 25 to 40 live cases, each one reviewed, is enough. Past that point, extra cases help less than fixing the two or three habits that keep costing you points.

Not every case counts equally. A case you read is not a case. A case you work silently on paper is half a case. A case done out loud, timed, with someone pushing back and a review afterwards, is the real thing, and the only kind worth counting.

With a partner, take turns. Giving a case teaches you almost as much as receiving one: from the other side of the table you see exactly how a muddled structure or silent maths comes across. Give feedback within five minutes of finishing, while it is fresh.

McKinseyNordwind Airlines: the vanishing marginProfitability · Medium

Nordwind Airlines: the vanishing margin

A good week 2 case: a classic profitability problem. Run it live with the AI interviewer, then review it with the scorecard below.

Interviewer

Our client is Nordwind Airlines, a short-haul carrier operating out of northern Europe. Over the past three years passenger numbers have grown 18%, but operating profit has fallen by roughly 40%. The CEO wants to understand what is driving this and what to do about it. How would you approach the problem?

Start the caseGuided, step by step

The review is where you improve. Spend about 20 minutes on it straight after each case. Score each part of the case, write down what happened at the moment it went wrong, and pick the drill that fixes it.

Keep every review in one running log. After ten cases, look for repeats. If 'lost the thread after the maths' appears four times, that is your priority for week 3, and it matters more than any new case type.

Stop adding, start sharpening. The final week is for rhythm and confidence, not new material.

• One case a day, at the time of day of your interview, in the format of the firm you are seeing.
• Ten minutes of mental maths daily, so your arithmetic is warm rather than rusty.
• Your fit stories out loud until each takes about two minutes, plus a clear answer to why consulting and why this firm.
• Your review log, not a textbook. Your three most common mistakes are the ones to guard against.
• Logistics: video set-up, plenty of squared paper, two pens, the time zone and the names of your interviewers if you have them.
• The day before: one easy case in the morning, then stop. Sleep will do more for you than a final case.

The best time to do your first case is before you feel ready. Start with the featured sizing case on this page: it is short, it needs no business background and it has a built-in sanity check. Then try the growth case below once you have three or four cases behind you.

BainBrightPath Tutoring has stalledGrowth Strategy · Medium

BrightPath Tutoring has stalled

For week 2 or 3: a candidate-led growth case where you choose what to look at next.

Interviewer

BrightPath is an online tutoring marketplace connecting school students with subject tutors. After three years of 60%+ annual growth, revenue has been flat for five quarters. The founders want to get back to growth. Where do you want to start?

Start the caseGuided, step by step