McKinsey Case Interview Examples: Worked Practice Case (2026)

Format

How McKinsey cases work

Most firms run candidate-led cases, where you set the direction and ask for the data you want. McKinsey is the main exception. The interviewer leads, moving you through a fixed set of questions: how you would structure the problem, what an exhibit tells you, a calculation, a brainstorm, and a final recommendation.

That changes how you prepare. You do not need to steer the case, but you do need to perform well on every single question, because each one is assessed on its own.

The interviewer controls the pace

You will not choose which branch to explore. Build a strong structure anyway, since it shows how you think even if the interviewer takes the case somewhere else.

Every question counts

A weak brainstorm cannot be rescued by strong math later. Treat each question as a small, complete answer: lead with your point, support it, and state the implication.

Half of each interview is the PEI

First-round interviews typically pair one case with one personal experience interview question. The PEI carries real weight, so prepare it as seriously as the case.

McKinsey publishes four practice cases on its careers site: Beautify, Diconsa, Electro-Light, and Talbot Trucks. Work through all four. The case below follows the same question-by-question format, with answer checks built in.

Question types

The five question types

Almost every McKinsey case is built from the same five kinds of questions. Get good at each one separately and the full case takes care of itself. Pick a tab to see what each sounds like, what is being assessed, and the mistake that costs candidates most often.

What it sounds like: "What factors would you look at to decide whether the client should launch this product?"
What is being assessed: Whether your buckets are complete, do not overlap, and are specific to this client rather than a memorized framework.
Common mistake: Listing generic categories like "market, competition, company" with no detail underneath. Go one level deeper and tailor each bucket to the case.

Practice case

Worked practice case: Riverside Pharmacy

This is an original case written in McKinsey's interviewer-led style. The interviewer asks each question in turn, and you answer only what is asked. Answer each step out loud or on paper before you reveal the model answer. The suggested times match a strong candidate's pace.

Growth and new businessHealthcare retailAbout 25 minutes

Riverside Pharmacy: should it open in-store clinics?

Your client is Riverside Pharmacy, a US pharmacy chain with 2,000 stores. Front-of-store sales have been flat for three years, and the CEO sees walk-in health clinics inside stores as a way to grow and bring more customers through the door. Riverside has run a one-year pilot with a small number of clinics. The CEO has asked McKinsey whether Riverside should roll clinics out across its network, and if so, where.

If you ask clarifying questions, the interviewer shares:

Riverside's stores split into 600 urban, 900 suburban, and 500 rural locations.
Clinics are staffed by nurse practitioners and treat minor illnesses, give vaccinations, and run basic health screenings.
Every store has room for a clinic. One-time build costs are out of scope for now.

0 of 6 steps revealed

Structure question

Take about 2 minutes

Interviewer: What factors would you consider in deciding whether Riverside should roll out clinics?
I would look at four areas:
- Demand: how many visits a clinic can attract, which depends on local population, insurance coverage, and nearby urgent care and doctors' offices.
- Clinic economics: revenue per visit, variable cost per visit, and the fixed cost of staffing and running each clinic.
- Benefit to the pharmacy: extra prescriptions and front-of-store purchases from clinic patients, which may matter as much as the clinic itself.
- Ability to execute: hiring enough nurse practitioners, state regulations, and protecting the pharmacy's reputation if care quality slips.
Why it works: the benefit-to-pharmacy bucket shows you understood why a pharmacy would want clinics in the first place. That kind of client-specific thinking is what separates a strong structure from a generic one.
Exhibit question

Take about 3 minutes

Interviewer: Here are results from the pilot. Each visit brings in $110 of revenue and costs $40 in supplies and billing. Each clinic costs $620K a year to run, and clinics are open 350 days a year. How many visits per day does a clinic need to break even, and what does that tell you?

Exhibit 1: Average daily visits per pilot clinic, by store location

Store location Pilot clinics Average visits per day

Urban 8 32

Suburban 10 24

Rural 6 14

Illustrative data for practice.

Break-even visits per day
Math question: the pharmacy halo

Take about 3 minutes

Interviewer: The pilot also found that 60% of clinic visits lead to a prescription filled at Riverside's pharmacy, and each prescription earns $15 in profit. Including that, what is the new break-even?

Break-even visits per day
Math question: sizing the rollout

Take about 2 minutes

Interviewer: If Riverside opens clinics in all of its urban and suburban stores, how much annual profit would the clinics generate, including the pharmacy halo?

Annual profit ($M)
Creative question

Take about 2 minutes

Interviewer: The CEO does not want to give up on rural stores. What could Riverside do to make rural clinics work?
There are three ways to close the gap: more visits, lower fixed cost, or more value per visit.
- More visits: seasonal vaccination drives, contracts with local employers for workplace screenings, and ongoing check-ins for patients managing chronic conditions.
- Lower fixed cost: share one nurse practitioner across two nearby stores, open fewer hours, or use a telehealth room where a remote clinician sees patients with an on-site assistant.
- More value per visit: add services like basic lab tests, and partner with insurers who want to steer patients away from costly emergency room visits.
Naming the three levers first turns a list of ideas into an argument. The telehealth idea is worth flagging as the most promising, since it attacks the biggest problem: fixed cost.
Synthesis question

Take about 1 minute

Interviewer: The CEO just walked in. What do you recommend?

Store location	Pilot clinics	Average visits per day
Urban	8	32
Suburban	10	24
Rural	6	14

Math

McKinsey case math quick check

McKinsey math questions are rarely hard in isolation. The challenge is doing them cleanly and out loud while someone watches. Try these four without a calculator, and aim for under a minute each.

A market is worth $4B today and grows 5% a year. How big is it in two years?

Market size ($B)

A product sells for $50, costs $20 per unit to make, and needs $1.2M a year in fixed costs. How many units must it sell to break even?

Units

The client sells 1.8 million units in a market of 12 million units. What is its market share?

Market share (%)

Revenue is $250M. Profit margin falls from 12% to 9%. How much profit did the client lose?

Profit lost ($M)

Behavioral

The personal experience interview

Every McKinsey interview pairs the case with a personal experience interview, or PEI. Instead of skimming several stories, the interviewer picks one and goes deep, asking follow-up after follow-up about what you did, why you did it, and how others reacted.

McKinsey's own interviewing page recommends coming prepared with two personal examples for each of the four areas it assesses. A few things make those stories hold up under questioning:

Pick stories where you drove the outcome. The interviewer wants your actions, not the team's. If you cannot explain a decision you made, choose a different story.
Know the details cold. Expect questions about specific conversations, what you would change, and how you handled pushback.
Practice being interrupted. Have a partner cut in with follow-ups so you get comfortable answering off script.

The McKinsey interview guide includes reported PEI questions you can use to test your stories.

Assessment

Before the interviews: Solve

For most consulting roles, McKinsey screens candidates with Solve, a gamified problem-solving assessment, before any interviews. McKinsey says no preparation is needed, but many candidates still practice so the format and time pressure do not catch them off guard. The Redrock guide walks through one of the games in detail.

Prep plan

A two-week prep plan for a McKinsey case

Days 1 to 3
Practice structure questions on new prompts until you can give a tailored, two-level structure in two minutes. Start with the frameworks guide.
Days 4 to 6
Drill math daily, saying each setup out loud before you calculate. Break-even, growth, market share, and margin questions come up constantly.
Days 7 to 8
Work through exhibits. For every chart, give the single most important insight in one sentence before anything else.
Days 9 to 11
Run full interviewer-led cases with a partner, including McKinsey's four published cases. Redo Riverside from memory and time yourself.
Days 12 to 14
Build and pressure-test your PEI stories: two per area, each able to survive ten minutes of follow-up questions.

Keep preparing

McKinsey interview guideRounds, format, and reported PEI questions. McKinsey Solve HubSimulators for all three Solve games. McKinsey salariesPay by level and region. McKinsey application deadlinesWhen to apply for the next cycle.

FAQ

Frequently asked questions

Are McKinsey case interviews interviewer-led?

Yes, in most cases. The interviewer asks a set sequence of questions, typically covering structure, exhibits, math, brainstorming, and a final recommendation, and assesses each answer on its own.

How many interviews does McKinsey run?

A typical process has two rounds after the Solve assessment. The first round usually has two interviews with associates or engagement managers, each with one case and one PEI question. The final round has two or three interviews with partners.

Does McKinsey publish its own practice cases?

Yes. McKinsey's careers site has four sample cases with suggested answers: Beautify, Diconsa, Electro-Light, and Talbot Trucks. They are the best starting point for understanding the format.

How should I prepare for the PEI?

McKinsey recommends two personal examples for each of the four areas it assesses. Choose stories where you personally drove the result, and practice answering detailed follow-up questions about your decisions.

What kinds of cases does McKinsey give?

Anything from profitability and market entry to new product launches, operations, and public sector work. The format stays the same even when the industry changes, which is why practicing each question type matters more than memorizing case types.

Is the Riverside Pharmacy case a real McKinsey case?

No. It is an original practice case written to match McKinsey's interviewer-led format. All numbers are illustrative.

Sources

McKinsey & Company, Interviewing at McKinsey. mckinsey.com. Accessed September 2026.
IGotAnOffer, McKinsey Case Interview guide. igotanoffer.com. Accessed September 2026.
Management Consulted, McKinsey Case Interview. managementconsulted.com. Accessed September 2026.
MyConsultingOffer, McKinsey Case Interview guide. myconsultingoffer.org. Accessed September 2026.

Case Prep is an independent practice platform and is not affiliated with, authorized by, or endorsed by McKinsey & Company. The Riverside Pharmacy case, example questions, and all data on this page are original teaching material.

McKinsey Case Interview Examples: A Worked Practice Case