Most candidates start McKinsey prep on someone else's roundup and never open the firm's own careers pages until the week of the interview. That is backwards. McKinsey already publishes, for free, the format description, six practice cases with suggested answers, the Personal Experience Interview themes, a Solve assessment page and FAQ, and interview videos. Those materials sit closer to what the room actually rewards than any PDF you found in a Slack channel.
The thesis is simple: rank McKinsey's published stack first, university and institutional free material second, and third-party volume third. Paid coaching and graded AI practice help after that, not instead of it. By the end you will have a ranked free stack, a reproducible hour budget for a four-week cycle, and one assignment you can finish today without a credit card.
CoachNed is not affiliated with McKinsey.
What McKinsey publishes, ranked
Open these in order. Do not skip to casebooks until you have worked items one through five aloud at least once.
| Rank | Resource | What it is for | Link |
|---|---|---|---|
| 1 | Interviewing page | Format, PEI themes, problem-solving interview description, links to sample cases | Interviewing at McKinsey |
| 2 | Official practice cases | Six interviewer-style cases with prompts, exhibits, and suggested approaches | Beautify, Diconsa, Electro-Light, GlobaPharm, National Education, Talbot Trucks (linked from the interviewing page) |
| 3 | PEI description on the same page | Four themes; firm asks you to prepare two examples per theme | Same interviewing page, Personal Experience Interview section |
| 4 | Solve page and FAQ | What the digital assessment is, integrity rules, device requirements, how results are used | Solve; Solve FAQ (PDF) |
| 5 | Official interview videos | Cadence of the case and recruiting Q&A from McKinsey's own channel | Case study interview; Hiring team Q&A |
McKinsey's interviewing page is explicit about the sequence for most client-facing roles: a personal experience interview, then a problem-solving interview, with an expertise interview only when the role needs it. The firm tells you to come with "two personal examples that demonstrate how you've made an impact in each of the four areas" under the PEI section. That is eight stories, not three polished ones you recycle. Treat that as a published requirement, not folklore.
The sample cases are the only free cases where the suggested answer was written to reflect McKinsey's own evaluation language rather than a student's reconstruction. Start with Beautify and Electro-Light for commercial arithmetic, Diconsa and National Education for public and social sector reasoning, and GlobaPharm and Talbot Trucks for M&A and product decisions.
How to use one official case so it actually transfers
Reading Beautify on a train does not count as practice. From the interviewer's chair, I only believe a candidate has "done" a published case when three things happened: they answered every quantitative prompt out loud without looking at the answer key, they compared their structure to the suggested approach after the fact, and they wrote down the one habit they would change next time.
Here is a napkin version of that habit, using invented figures so you can reproduce the arithmetic without spoiling McKinsey's PDF. Harbor Rail runs 40 regional freight terminals. Average revenue per terminal is $4.2M a year. A digital booking build costs $28M up front and $1.5M a year to run. The team expects a 6% revenue lift in year one from fuller loads, then flat. How many years until the investment turns profitable if revenue does not grow after year one?
| Step | Calculation | Result |
|---|---|---|
| Portfolio revenue today | 40 x $4.2M | $168M |
| Year-one incremental revenue | $168M x 6% | $10.08M |
| Year-one net after run cost | $10.08M − $1.5M | $8.58M |
| Years to recover $28M at that net | $28M / $8.58M | About 3.3 years |
Answer that earns a mark: "Call it three and a third years if the 6% sticks and nothing else moves. The decision turns on whether year-two revenue still carries that lift; if half of it erodes, payback stretches past five years, so I would stage the build at the ten highest-load terminals first." Same arithmetic as a silent "3.3 years," different score on judgment and synthesis.
Do that exercise on each of McKinsey's six cases before you chase volume. The official case study interview video puts the problem-solving portion at roughly 25 to 30 minutes of a typical interview, which is how long you should stay coherent without notes.
PEI from the firm's words, not from templates
McKinsey's page asks for depth on your specific role, the actions that were critical, the challenges, and the impact. Recruiting leadership has said publicly that the PEI is about past behaviors in situations similar to the job, not about having held a consulting title already (see the hiring-team conversation on McKinsey Unpacked). University career offices amplify the same point without selling anything: Yale's Office of Career Strategy keeps a McKinsey PEI landing page and a free consulting interview overview PDF that distinguishes interviewer-led McKinsey-style cases from candidate-led formats. Penn Career Services circulates a free consulting preparation case book for partner practice.
Ned's rule. Prepare eight stories mapped to McKinsey's four PEI themes before you memorize a single framework. A candidate who can take twenty minutes of follow-ups on one real story beats a candidate who has fifty frameworks and three thin anecdotes.
Write each story so the first ninety seconds name the decision, your role, the obstacle, and the measurable result. The rest of the minutes exist for the interviewer to dig. If your story collapses when someone asks "what did you do when X disagreed," it is not ready.
Solve: what the firm states versus what candidates invent
McKinsey describes Solve as a gamified assessment of problem-solving. The firm says there is no need to prepare, that each task starts with an untimed tutorial, that the assessment runs on PC or Mac, and that results are considered with the rest of the application rather than as a lone pass-fail gate. The 2024 FAQ PDF repeats those points and forbids AI tools, notes, recording, and assistance from others. McKinsey's own careers blog on how Solve was built with Imbellus is useful context on why the format exists (Innovating recruiting through online gaming).
What the firm does not publish: fail rates, exact module mix for your invitation, or scoring weights. Module names you see on forums (Redrock, Sea Wolf, Sustainable Futures Lab) are candidate-reported labels, not a guarantee of what your email will assign. Treat them as folklore until your invitation names the tasks. Quiet room, working laptop, no helpers: that is the free preparation McKinsey itself endorses.
If you still want a dry run of the kind of thinking those games reward, use that time after the official FAQ, not instead of it.
University and other free primary sources
After the firm stack, add free material that comes from universities and career offices, not from prep companies.
| Source | Why it helps | Caveat |
|---|---|---|
| Penn Career Services consulting case book (PDF) | Free interviewer and interviewee slides for partner practice | Older packaging; still useful for live mocks |
| Yale OCS consulting channel and PEI page | Institutional framing of PEI and firm timelines | Links out; verify current deadlines on McKinsey's site |
| Chicago Booth Management Consulting Group | Describes a student-compiled casebook and coaching structure | Casebook access is often member-gated; use what is public |
| MBA consulting club casebooks (Wharton, Booth, Columbia, and peers) | Volume for partner-led practice after the six official cases | Student-written answers; never treat them as McKinsey's key |
Use university casebooks for timed partner reps, not passive reading.
Honest free CoachNed surfaces
CoachNed is a practice product, not McKinsey, and not free forever for everything. What is genuinely open without a card:
| Surface | What you get | Access |
|---|---|---|
| /start | Five-minute first rep: three typed turns of a case, instant scores | Works without an account |
| /drills/quick-math | Quick math drills | Free forever |
| /mckinsey-sea-wolf, /mckinsey-red-rock, /mckinsey-sfl | Solve-style practice games | Open during the free week |
| Full case library, voice interview, PEI practice | Graded full cases and behavioral | Everything open for seven days, no card; then $120 for a recruiting season or $49 a month |
Use these for feedback after you have worked McKinsey's six cases. Do not substitute a simulator for the firm's FAQ on integrity rules.
A four-week free hour budget you can reproduce
Assume you have 10 hours a week for four weeks: 40 hours total. Here is an allocation that matches the ranking above. Invent your own week-one calendar; keep the proportions.
| Block | Hours | What you do |
|---|---|---|
| McKinsey interviewing page + videos | 3 | Read once, watch both videos, write the four PEI themes on a card |
| Six official cases, spoken aloud | 12 | Two hours per case: attempt, then compare to suggested approach |
| PEI story bank | 8 | Eight stories, two per theme, recorded once each |
| Solve FAQ + one quiet practice block | 3 | Read FAQ; dry-run laptop and room; optional Solve-style practice after |
| University casebook with a partner | 10 | Five partner cases, debrief each |
| Math hygiene | 4 | Daily 15 minutes on quick math or napkin arithmetic |
That is 40 hours. If you only have 20, cut partner cases to two and keep all twelve hours on McKinsey's own cases. Volume without format is how candidates arrive fluent in frameworks and still lose the first ten minutes.
Practice this week
Today, not "sometime before applications": open Beautify, close the answer section, and work every quantitative prompt out loud with a timer set to 30 minutes. Write one sentence on what you would change. Then run /start once for a scored first rep, and spend fifteen minutes on /drills/quick-math. If your free week is active, add one pass on /mckinsey-red-rock after you have read McKinsey's Solve FAQ, not before.
Frequently asked questions
Are McKinsey's practice cases enough on their own?
No. They teach format and evaluation language. You still need spoken volume and PEI depth. Six official cases plus a university casebook with a partner is a stronger free stack than fifty unread PDFs.
Does McKinsey say you should practice for Solve?
McKinsey's Solve page and FAQ say no preparation is required and that each task includes an untimed tutorial. Quiet focus and a working PC or Mac are the free steps the firm itself emphasizes. Anything beyond that is optional candidate preference, not firm guidance.
How many PEI stories do I need?
McKinsey's interviewing page suggests two personal examples for each of the four themes. Plan for eight distinct stories you can defend under follow-ups.
What is free on CoachNed versus what needs a plan?
/start and /drills/quick-math are open without a card. Solve-style practice at /mckinsey-sea-wolf, /mckinsey-red-rock, and /mckinsey-sfl is available during the free week. Broader access stays open for seven days, then $120 for a season or $49 a month.
Should I watch unofficial case demos on YouTube?
Watch McKinsey's own case study interview and hiring-team videos first. Unofficial demos vary widely in quality; none of them rewrite the firm's published suggested approaches.
Sources
- Interviewing at McKinsey — format, PEI themes, links to sample cases. Checked 2026-09-24.
- Beautify practice case — official sample case. Checked 2026-09-24.
- Diconsa practice case — official sample case. Checked 2026-09-24.
- Electro-Light practice case — official sample case. Checked 2026-09-24.
- GlobaPharm practice case — official sample case. Checked 2026-09-24.
- National Education practice case — official sample case. Checked 2026-09-24.
- Talbot Trucks practice case — official sample case. Checked 2026-09-24.
- Solve, McKinsey's assessment game — official Solve description and integrity rules. Checked 2026-09-24.
- Solve FAQ PDF (2024) — device requirements, scoring context, preparation guidance. Checked 2026-09-24.
- Innovating recruiting through online gaming — McKinsey careers blog on Solve's development. Checked 2026-09-24.
- Interviewing with McKinsey: Case study interview — official case interview video. Checked 2026-09-24.
- McKinsey Hiring Team Answers Your Questions — official recruiting Q&A including Solve. Checked 2026-09-24.
- Yale OCS: McKinsey PEI — university PEI overview. Checked 2026-09-24.
- Yale OCS consulting interview overview PDF — interviewer-led vs candidate-led framing. Checked 2026-09-24.
- Penn Career Services consulting preparation guide — free university practice cases. Checked 2026-09-24.
- Chicago Booth Management Consulting Group — student casebook and prep structure description. Checked 2026-09-24.