The four practice cases on McKinsey's interviewing page come with suggested answers, cost nothing, and were written by the people who will score you. In my experience they are also the least-used item on a candidate's list. Ask a first-round candidate what they prepared with and you hear a prep company's name; the firm's own page comes up perhaps one time in five, and that is my rough count from the interviewer's chair, not a survey.
So here is the thesis. Rank free case interview resources by who wrote them and what happens to the author if you get better. The firms want you to walk in knowing the format, because a candidate confused by the format tells them nothing, so their free material is complete. A prep company's free tier exists to sell its paid tier, so it is a sample by design. And no free resource from anyone contains the one thing that moves a score, which is somebody other than you grading the rep.
By the end of this you will have an audit of what five firms actually publish as of today, a method for turning one static prompt into three scored reps, and a price list for the part that free does not cover.
Read the publisher before you read the page
Free is not one category. It is four publishers with four different reasons for giving material away, and the reason predicts the quality more reliably than the design of the website does.
| Publisher | Why it is free | What it does well | What it will not do |
|---|---|---|---|
| The firm's careers site | They want the interview to measure your thinking, not your surprise at the format | Prompts, model answers, and the firm's own words on what it looks for | Score you; nothing on the page listens back |
| Business-school consulting clubs (casebooks) | Members wrote them for each other; the PDFs leak out of the clubs every year | Volume: 20 to 40 prompts and exhibits per book | Edit itself; frameworks date, and arithmetic errors survive for years |
| Prep companies' free tiers | A sample that sells the paid tier | An occasional clear explainer or a single sample case | Give you the part you actually need; that part is paid, by design |
| Your phone's voice recorder | Nobody wrote it; it is a recorder | Turn a silent rep into an audible one you can count | Judge you on its own; you supply the counts |
Notice what is missing from every row. Nothing in the free universe scores you. That is not a defect of any particular resource; it is the definition of the category. Hold onto that, because most lists of free resources are really lists of prompts, and prompts were never the scarce input.
What the firms publish, audited
I opened each page on 2026-09-24. Firms move these around, so treat the table as a snapshot and the links as the way in.
| Firm | On the page today | Answer key | Best used for |
|---|---|---|---|
| McKinsey | Four practice cases (Beautify, Diconsa, Electro-Light, Talbot Trucks) with "logic, thought processes, and suggested answers", previews of PEI questions, and a table of what AI use is allowed in prep | Yes | Interviewer-led structure and the firm's own PEI framing |
| BCG | A description of the case (there "isn't always a single right answer"), a do and don't list, a video with an associate, and OneDay@BCG, a free job simulation | No worked case in the page text | Learning what BCG says it is looking for |
| Bain | Practice cases with show-the-answer steps, such as Coffee Shop Co., which tells you to take one to two minutes to structure before speaking | Yes, step by step, including a breakeven | Candidate-led cases and market sizing |
| Deloitte | An interactive case tool for entry-level consulting candidates, split by practice area, 15 to 20 minutes per case, untracked; a five-step approach | Yes, check-your-work after each question | Deloitte's format, which is more guided than MBB |
| Oliver Wyman | A six-step case method (pinpoint the issue, break it down, pick an approach, analyze, use numbers, recommend) and practice samples | Varies by sample | The reasoning sequence OW says it wants to hear |
Some details worth the click.
McKinsey's page is unusually explicit about tools. Its table marks "practicing interview questions" and "asking AI to explain concepts or frameworks as part of your prep" as encouraged, and "generating real-time answers during an interview" as not allowed. It also says of Solve, its gamified assessment, that "there's no need to prepare." Take the first statement at face value. Take the second with the knowledge that nobody was ever marked down for knowing what a game looks like before sitting it.
Bain's Coffee Shop Co. is the best free worked case I know of, because it shows its arithmetic. Price £3, variable cost £1, £245,610 to open, and £163,740 a year to run, so 2Q equals 409,350 and breakeven is 204,675 cups. You can check every step, which is rarer in casebooks than it should be. Bain's interviewing page also states the consulting sequence plainly: a digital assessment, then case interviews.
BCG's case preparation page carries no worked case in the text I could read, but it does list the verbs: structure your approach, ask thoughtful questions, analyze data, perform quick calculations, and identify the most important factors, while communicating clearly. Five verbs, and every scoring sheet I have used maps onto them. Its don't list is shorter and worth memorizing: overcomplicate solutions, ignore feedback, stay silent, interrupt.
Deloitte's tips page says you are "not expected to provide the 'right' answer, but rather to clearly convey your logic and thought process," and its five steps end with "outline next steps and expected results." Most candidates stop at the recommendation. Deloitte tells you, in writing, that it wants the step after.
Oliver Wyman's page frames the interviewer as your client: "They want you to solve the problem, and can help you to do so." That is the most useful sentence a nervous candidate can read, and it is free.
Smaller firms publish too. Kearney's careers site has a "Crack the case" section with a worked promotion-planning example. Go in through each firm's careers menu rather than a saved link; these pages are reorganized more often than they are announced.
Casebooks: free prompts, unpaid editors
Every autumn a fresh set of consulting-club casebooks from the big MBA programs circulates as PDFs. They are the largest free source of prompts and exhibits there is, and they have two problems the firm pages do not.
First, they were written by second-year students in a hurry, and nobody edits them afterward. I have seen exhibits whose segments do not sum to the total and model answers with the decimal in the wrong place. Second, the framework pages at the front are the most-read and least-useful section. They teach you to recite categories, and reciting categories is the thing an interviewer marks down.
Use them as prompt and exhibit libraries only. Cover the model answer, do the case aloud, and when your number disagrees with theirs, check theirs. Finding the error is a better rep than agreeing with the key.
The thing no free resource contains
A model answer is an answer key for the destination. The scoring sheet grades the route: whether the structure came before the data, whether the set-up was spoken before the arithmetic, whether the recommendation led the close. Nothing printed can see the route. Only a listener can, and a listener with a rubric is the entire cost of case prep.
Which is why the sensible way to think about free is as a constraint on money, and then to notice that the real budget is hours. The role you are practicing for pays a median of $101,860 a year for management analysts in the United States, according to the Bureau of Labor Statistics for May 2025, with about 94,100 openings projected each year over the decade. Against that, the money side of prep is small. The hours side is not, and every way of getting scored spends hours differently.
| Way to get a rep scored | Money | Your hours per scored full case | Whose rubric |
|---|---|---|---|
| Record yourself and count | $0 | About 1, including the scoring listen | Yours, written down before you start |
| Campus club or peer swap | $0 | About 2, once you count scheduling and the half hour you spend interviewing them back | Usually nobody's; bring a printed one |
| AI interviewer such as CoachNed | $0 for seven days, no card; then $120 for a recruiting season or $49 a month | About half an hour, debrief included | Seven fixed dimensions, the same every time |
| Private coach | $200 to $400 an hour is common, in my estimate | 1 | The coach's, which is the point |
The first two rows are genuinely free and genuinely useful, on one condition: a rubric exists before the case starts. A peer session where both of you improvise feedback is not free. It costs two hours and returns "good energy."
Ned's rule. Judge a free resource by who wrote it and what happens to them if you get better. The firm wants you good in the room; everyone else wants you back on the site. Read the firm's page first, and read it twice.
Worked example: one free prompt, three scored reps
Here is how to get scored reps out of a static case for nothing but your phone. The case is invented.
Kestrel Bikes runs 12 bicycle shops in one region. Revenue has been flat at $14.4 million for two years while profit fell from $1.1 million to $0.7 million. The owner asks whether to close her two weakest stores.
Rep one, structure. Read the prompt, sit in silence for 90 seconds, then speak your structure for two minutes into the recorder. Listen back and count three things: branches (three or four), whether each branch is tied to the question with a "because," and whether you said where you would start. A good opening here does not accept the question as posed. It says, roughly: "Before I evaluate closing two stores, I want to know whether two stores can explain a $400,000 profit decline. My branches are store-level economics, chain-wide cost creep, and margin mix." That move is what the sheet calls business judgment.
Rep two, math. Give yourself the data an interviewer would. Each weak store sells $800,000 at a 35 percent gross margin; its costs are $110,000 rent, $150,000 staff, and $30,000 other. If a store closes, 25 percent of its sales move to the nearest Kestrel shop and are absorbed by existing staff. Breaking a lease costs six months' rent.
Speak the set-up before any number: "Contribution is gross profit minus store costs. The closure gain is the loss I stop making, plus the gross profit I keep on transferred sales, minus the exit cost." Then compute. Gross profit per weak store is 0.35 times 800,000, or 280,000. Costs are 290,000. Each store loses 10,000 a year, so 20,000 for the pair. Transferred sales are 200,000 per store, worth 70,000 of gross profit each, so 140,000. Lease exits cost 55,000 each, so 110,000 once. Year one: 20,000 plus 140,000 minus 110,000, which is 50,000. Every year after: 160,000.
Now the sentence the interviewer is waiting for. "Closing both stores adds about $160,000 a year from year two, roughly 1 percent of revenue. That recovers 40 percent of the $400,000 decline, so the two stores are not the main story. I would close them, and I would spend the rest of this case on where the other $240,000 went." Score the rep on four counts: set-up spoken before arithmetic, answer rounded, answer interpreted against the question, and the assumption that matters (the 25 percent transfer) named aloud.
Rep three, the close. Read your own notes for 30 seconds, then deliver a 60-second recommendation. Count: was the recommendation the first sentence, did it carry a number, and did you give one risk (the transfer rate is a guess; at 10 percent the year-one gain turns negative) and one next step.
Twelve minutes, three reps, four or five counts each, and a page of scores in your own handwriting. Repeat with the next free prompt. This is what the firm pages are for.
Free things that cost you
Some free objects are expensive, because the currency is your hours and your habits.
- Listicles of free resources. Thirty open tabs of prompts is a way to spend an evening not doing a case. A dozen prompts is enough to start, and the firm pages alone supply that.
- Official videos, watched. The firms publish good interview-prep videos. Watching one is orientation, and orientation is finished after the first viewing. The second viewing is procrastination with a consulting logo on it.
- Free trials that ask for a card. Not free. A trial that needs no card and states its end date is a free week; anything else is a subscription with a delay.
- Peer cases without a rubric. Covered above. Print the rubric or skip the session.
- PDFs read in silence. You used the free object and skipped the free behavior. The behavior, speaking, was the point.
Practice this today
Open one firm case. Bain's Coffee Shop Co. or any of McKinsey's four will do. Run the three reps above with your phone, and write the counts down before you look at the model answer.
If you want the counting done for you, CoachNed's five-minute first rep takes three typed turns of a case and scores them instantly, with no account. The math drill scores the spoken set-up problem from rep two against an answer key, and quick math is free forever. When you are ready for the full thing, the voice case with Ned runs about 18 minutes and ends in a seven-score debrief, and the case library has 64 original cases for when you have exhausted the firms' own. Everything is open for seven days, no card; then $120 for a recruiting season or $49 a month.
CoachNed is independent and not affiliated with McKinsey, BCG, Bain, Deloitte, Oliver Wyman, Kearney, or any other firm named here.
Frequently asked questions
Can you prepare for a case interview for free?
Yes, for everything except the score. The firms publish prompts, model answers, and their own account of what they look for; a phone recorder and a written rubric supply the feedback loop. Budget hours rather than money, and spend the hours speaking rather than reading.
Are McKinsey's practice cases free?
Yes. As of September 2026, McKinsey's interviewing page carries four practice cases with suggested answers, plus previews of its PEI questions, at no cost and with no sign-up.
Are MBA casebooks still worth using?
As prompt and exhibit libraries, yes. As teaching, no: the framework pages date quickly and the model answers are unedited student work, so check every number and treat a disagreement with the key as a rep in itself.
Is there a free case interview simulator?
Deloitte's interactive case tool is free and untracked, and CoachNed's first rep runs without an account. The difference is that Deloitte checks your answers while CoachNed scores how you got there, which is what the interview grades.
Sources
- Interviewing at McKinsey — the four practice cases with suggested answers, the PEI previews, the AI-use table, and the description of Solve. Checked 2026-09-24.
- BCG case interview preparation — BCG's current description of the case, the do and don't lists, and OneDay@BCG. Checked 2026-09-24.
- Bain practice case: Coffee Shop Co. — the worked market-size and breakeven steps and the one-to-two-minute structuring pause. Checked 2026-09-24.
- Interviewing at Bain — the consulting sequence of digital assessment then case interviews. Checked 2026-09-24.
- Deloitte case and scenario interview tips — the five-step approach, the "right answer" statement, and the entry point to Deloitte's interactive case tool. Checked 2026-09-24.
- Oliver Wyman interview preparation — the six-step case method and the practice samples. Checked 2026-09-24.
- Management analysts, Occupational Outlook Handbook (U.S. Bureau of Labor Statistics) — median pay of $101,860 in May 2025 and roughly 94,100 projected openings a year. Checked 2026-09-24.