L.E.K. Case Interview Practice: Free Case and Prep Resources
L.E.K. Consulting's interview preparation page publishes three practice cases, a brainteaser, Brewery Profits and Large Pharma Co., each with approach questions and no answers, plus seven tips for the case. Unlike McKinsey's sample cases, which include suggested answers, L.E.K.'s leave the answer to you: work each one out loud before you compare it with a worked solution.L.E.K. (opens in a new tab), read ; McKinsey (opens in a new tab), read
Free, no signup: 2 worked cases with model answers. Free, no card: your first full L.E.K.-style case with an AI interviewer. Paid: Pro $49/month for every case.
Updated ·By Esteban Ronsin·Founder · former Deloitte and Accenture Strategy consultant
Built and reviewed with former McKinsey, BCG and Bain consultants and interviewers.
Free L.E.K. interview prep resources
L.E.K. interview prep resources: what you get, whether it is free or paid, and the link
Resource
What you get
Free or paid
Link
L.E.K. interview preparation
L.E.K.'s own three case examples (a brainteaser, Brewery Profits and Large Pharma Co.) with approach questions but no answers, plus its seven tips for the case
1 L.E.K.-style case (1 growth), run out loud with an AI interviewer or step by step and scored on 7 skills; start with iPhone X-Change
Free + paid. The case list and a worked excerpt are public; a free account includes 1 full AI-graded case in voice or guided mode; Pro ($49/month) adds every case
Dunmore Cargo Bikes: market sizing case with answers Industry: Mobility. Difficulty: easy.1 math question.
How big is the annual US market for electric cargo bikes sold to urban delivery couriers, and is it big enough for a $10 million revenue goal? 5 questions, 1 exhibit, a model answer for each
Free. The whole case and every model answer, no account; the practice button opens a live case like it
Velmont Capital: M&A case with answers Industry: Consumer goods. Difficulty: medium.2 math questions.
Should private equity fund Velmont Capital buy outdoor apparel brand Cinderfell Outfitters at the $480 million asking price, and if not, what should it bid? 6 questions, 3 exhibits, a model answer for each
Free. The whole case and every model answer, no account; the practice button opens a live case like it
L.E.K. fit and behavioral questions answered out loud, with follow-up probes and structured feedback (choose L.E.K. on the page)
Free + paid. 1 behavioral or Learning Mode session with a free account; Behavioral Unlimited ($39/month, behavioral and PEI only) or any Pro plan adds more
Firm-style cases are practice cases written for Road to Offer or adapted from university consulting club casebooks, not the firm's own cases. Road to Offer is independent and not affiliated with L.E.K.
Try a free L.E.K.-style case now: no card, no signup
An original practice case written by Road to Offer in an L.E.K.-style format, not L.E.K.'s own case. Everything stays in your browser.
Used Devices Sizing: Sizing the US market for used phones, tablets and laptops
Market sizing first, as in L.E.K.'s own Large Pharma Co. example, which asks for an estimate before the decision built on it. The full version is iPhone X-Change, our library case adapted from the Duke Fuqua consulting club casebook, which files it as an L.E.K. market sizing case. L.E.K. (opens in a new tab), read
1Step 1: Read the case
Electronics Co. buys used phones, tablets and laptops from US consumers and resells them through its own online store. The CEO wants to know, as soon as possible, how big the US market for used devices is, category by category, and what that means for the business. How would you size it?
2Step 2: Ask clarifying questions
Open a question to hear the interviewer's answer.
What exactly does the client do?
Interviewer: It buys used devices from consumers and resells them online, direct to consumers, in the US only.
Which devices count?
Interviewer: Phones, tablets and laptops, plus an Other group (headphones, consoles, cameras). Size Other as 20% of the combined value of the three named categories.
Do you want units or dollars?
Interviewer: Market value in dollars, by category and in total.
Is the data you have annual, and does it start from global volumes?
Interviewer: You will get category volumes once you have a method. They don't say what period or geography they cover, so don't call the result annual.
Do you need an investment recommendation?
Interviewer: No. The CEO wants the market size, where it concentrates and the main risks.
3Step 3: Structure your answer
Take two minutes. Lay out how you would size the US used-device market, then say which route you would use and why.
2:00
Show what a strong structure covers
Plays the goal back: US market value in dollars, used devices only, by category and in total, ending in a summary for the CEO, not an investment call.
Picks one route for each category: units sold, times the share sold used, times the US share, times the average used price.
Sizes phones, tablets and laptops separately, then adds Other by its stated rule, 20% of the three combined.
Keeps a population route (US buyers, how often they buy, the share who buy used) as a cross-check, not a number to add.
Names the data limits up front: the volumes have no stated period or geography, so the result is not labelled annual.
Plans the so-what: which category holds most of the value, and the risks, such as used-device supply, quality control and buyers who prefer new models.
4Step 4: The interviewer's next question
The exhibit shows phones: 1.25 billion units sold, 20% of them used, 10% in the US, and an average used price of 50 dollars. What is the used-phone market value?
Show what a strong answer does
Units first: 1.25 billion × 20% × 10% = 25 million used US phones, then × 50 dollars = 1.25 billion dollars. A strong answer says both numbers out loud, notes that the volume has no stated period, so it does not call the figure annual, and moves on to tablets and laptops.
Flour costs rose 18% on a $4M flour bill, and prices went up 3% on $20M of sales. How much margin did Harbor lose?
Your answer
Flour went up by about $720K and the price rise brings in $600K, so the net hit is roughly $100K.
What worked
Split the change into a cost side and a price side before adding them up.
Could improve
$720K minus $600K is $120K, not $100K: state the exact net before rounding.
Model answer
Flour: 18% of $4M is $720K more cost. Price: 3% of $20M is $600K more revenue. Net margin loss: $120K.
Next time, say this
Cost is up $720K and price brings back $600K, so Harbor loses $120K of margin.
3
1
Choose a case
Cases matched to L.E.K.'s case types.
2
Solve it out loud
An AI interviewer asks, listens and follows up.
3
Get answer feedback
Feedback on every answer: what worked, what to fix.
What makes L.E.K. interviews different
Answers left to you.
L.E.K. publishes three case examples with five approach questions each and no solution, so you have to check your own work. Source: L.E.K., read (opens in a new tab)
Restate before you solve.
L.E.K.'s first tip is to repeat or paraphrase the question, state your assumptions and restate the facts; its second is to devise a coherent approach before you start. Source: L.E.K., read (opens in a new tab)
Commit, then rethink.
L.E.K. asks you to commit to a course of action while showing flexibility and a willingness to rethink in the face of new data. Source: L.E.K., read (opens in a new tab)
L.E.K.'s Large Pharma Co. example asks you to size the market for a new drug, then describe how you would price it: the number feeds the decision. Source: L.E.K., read (opens in a new tab)
Due diligence roots.
L.E.K. says its commercial due diligence for investors analyses the market, customers, competitors, operations and the business plan, and that it is known for challenging management plans. Source: L.E.K., read (opens in a new tab)
Each arrow opens the source: L.E.K., read Nov 9, 2026.
Key facts from L.E.K.'s own pages
Three practice cases.
A Brainteaser (planes between JFK and LAX), Brewery Profits (two brewers, one with volatile profits) and Large Pharma Co. (size and price a baldness pill). Source: L.E.K., read (opens in a new tab)
Take your time, gather your thoughts, stick to your approach, ask questions, formulate hypotheses, come up with an answer, be yourself. Source: L.E.K., read (opens in a new tab)
Each arrow opens the source: L.E.K., read Nov 9, 2026.
L.E.K.'s practice cases and interview pages, item by item
Everything L.E.K. publishes to prepare for its interviews, each opened on 9 November 2026. The first five items are on its interview preparation page; each line is our summary of the item's own page. Read on L.E.K.'s site .
L.E.K.'s practice cases and interview pages, item by item: level, area and what each one is, linked to L.E.K.'s page
Planes leave JFK and LAX every hour on the hour on the same five-hour route; leaving New York at noon, how many planes flying the other way do you pass? Five approach questions (clarify, what you know, logical traps, what matters, assumptions), no answer.
Two rival brewers report similar, steadily growing revenue, but Cheapo's profits grow steadily while Bourgeois' swing. Why, and what would you do as Bourgeois' CEO? Five approach questions, no answer.
A pharmaceutical client has a daily pill, IPP2, that regrows hair within three months. Estimate the size of its market and describe how you would price it. Five approach questions, no answer. Worked below.
Take your time, gather your thoughts, stick to your approach, ask questions, formulate hypotheses, come up with an answer, and be yourself, each with a line on what it means.
Four ways to prepare: campus case workshops, reading the business press, practising with people who work in strategy consulting, and reviewing the case studies on L.E.K.'s website.
What the interviews aim to learn (how you think, your strengths, why consulting and why L.E.K.), several rounds mixing experiential and case interviews, the one-office-per-year rule and each region's openings.
Show all 10
L.E.K.'s practice cases and interview pages, item by item, continued
Names Applied as an online assessment provider for certain London vacancies, and the automatic academic screen for London consulting roles (a 2:1 degree, AAB at A level with an A in Maths if taken). Last updated January 2020.
A London associate's process: online psychometric and math exams, then case-based interviews with fit questions, including a wedding market sizing where method mattered more than the figure.
A Boston associate's process: a first round of two interviews, one on case strategy and one more quantitative, then partners and principals; how he practised.
How L.E.K. describes its due diligence for private equity buyers: the market landscape, customers, competitors, operations and the business plan. Useful vocabulary for a diligence case.
Worked: Large Pharma Co., in L.E.K.'s seven case interview tips
A large pharmaceutical client has developed a pill, IPP2, that regrows hair within three months to the thickness it had at 15, and must be taken every day to keep it. L.E.K. asks you to estimate the size of the market for the drug and describe how you would price it. Read the official case (opens in a new tab)(read )
How you might work it is ours, not L.E.K.'s answer key.
1
Take your time
Play it back: a daily pill, results in three months, lost if you stop. Two asks, a market size and a pricing approach. State your assumptions before any math: the US first, the market as yearly revenue once uptake has settled, and a cosmetic drug patients likely pay for themselves.
2
Gather your thoughts
Jot down how the two halves link: revenue is patients on the pill times the yearly price, so the number of patients is the base for every price you test. Note what you would ask: approval and side effects, the countries in scope, and what people with hair loss use today.
3
Stick to your approach
Build the patient chain one link at a time and say each assumption out loud: adults, the share with noticeable hair loss (men and women separately), the share who would take a daily pill for a cosmetic result and can pay, then the share the drug reaches. Do not jump to price until the chain is done.
4
Ask questions
Ask for the data that moves the answer most: what existing treatments cost (cheap daily products at one end, a one-off surgical procedure at the other) and how many patients keep taking a daily drug after a year.
5
Formulate hypotheses
Say where you think the price lands and why: priced on the value of the result, between the daily products and surgery, not on what the pill costs to make. Add the second hypothesis the daily dose implies: revenue depends on patients staying on it, so keeping them matters as much as the price.
6
Come up with an answer
Give one market number and one price, name the assumption most likely to be wrong (the share the drug reaches), and say how the answer moves if the interviewer changes it. Then compare your numbers with a worked solution; our L.E.K. practice cases page runs one.
L.E.K. calls the interview “your opportunity to show us how you think”: approaching a business problem and using data and your own experience to reach and defend a conclusion. Source: L.E.K., read (opens in a new tab)
Why L.E.K. specifically
L.E.K. says its interviews aim to understand your motivation for consulting in general “and a career with L.E.K. specifically”, along with your strengths. Source: L.E.K., read (opens in a new tab)
Method over the perfect number (London)
A London associate wrote that “the key was not necessarily getting the right answer but demonstrating structured problem-solving skills”, and checking the result afterwards. Source: L.E.K., read (opens in a new tab)
Storytelling (Boston)
A Boston associate wrote that his first round included background and behavioral questions such as “Why do you enjoy hockey?”, which he took as a test of storytelling. Source: L.E.K., read (opens in a new tab)
Each arrow opens the source: L.E.K., read Nov 9, 2026.
The L.E.K. interview process, and what trains each step
1
Application to one office
L.E.K. accepts an application to only one of its global offices per year and says it reviews every application; selected candidates are invited to interviews.
L.E.K.'s recruitment privacy notice says candidates for certain London (UK) vacancies may get an online assessment from Applied, and a London associate wrote on L.E.K.'s blog in 2023 that the process included online psychometric and math exams. L.E.K.'s global pages name no test, so follow your invitation.
Several rounds of case and experiential interviews
L.E.K. says the process differs slightly by region and by the level you apply for, and generally runs several rounds that mix experiential interviews about your background with case interviews; both quantitative and strategic cases are possible.
L.E.K. uses case interviews to see how you approach a business problem and reach and defend a conclusion with data. Its tips: restate the question and your assumptions, plan a coherent approach, ask for the information you need, share hypotheses as data arrives, and commit to an answer while staying open to new data. Its Large Pharma Co. example asks you to size a market, then price the product.
L.E.K. says its interviews aim to understand your strengths and your motivation for consulting and for L.E.K. specifically, alongside questions about your professional background.
Candidates report a written case in some final rounds, most often in Boston (US): you analyse a pack of slides alone, then present a recommendation and take questions. L.E.K.'s own pages do not mention one, so confirm it with your recruiter.
Missing from L.E.K.'s pages: who leads the case, how long each interview lasts, how many rounds each office runs, how answers are scored, whether there is a written case, which offices outside London use an online test, and when offers are made.
12 L.E.K.-style interview questions
In our words, not L.E.K.'s, grouped by L.E.K.'s own case tips, plus the online test some London roles use and the experiential interview, with what a strong answer does.
Take your time, gather your thoughts (tips 1 and 2)
L.E.K.: repeat or paraphrase the question, state your assumptions, then devise a coherent approach.
1A private equity fund is weighing a bid for a chain of pet grooming salons and asks whether the market is big enough for the chain to double in five years. What do you play back before you start?
What a strong answer does: Restates the real question (is there room to double, not only how big the market is), fixes the geography and the time frame, states one or two assumptions out loud and stops asking once it can lay out a plan.
2How many electric bikes are sold in the US each year? Lay out your approach before any math.
What a strong answer does: Picks one route, such as households or riders by segment times how often they buy, names a supply-side cross-check, and says which assumption it will test first.
Stick to your approach, ask questions (tips 3 and 4)
L.E.K.: move methodically through each issue, point by point, and ask for the information you need.
3An investor asks you to test a regional bakery chain's plan to grow revenue by half in three years. How do you structure the work?
What a strong answer does: Splits the plan into market growth, share gains and new stores or channels, asks what the plan assumes for each, and checks each against the market, customers and competitors, the way L.E.K. describes its due diligence.
4Halfway through your sizing, the interviewer says your share of buyers looks high. What do you do?
What a strong answer does: Asks what the interviewer knows, changes that one input, recomputes out loud and says how the answer and the decision move, without restarting the whole tree.
L.E.K.: share your thought process as information is revealed.
5Two software companies have similar, steadily growing revenue, but one's profit swings far more from year to year. What is your first hypothesis?
What a strong answer does: Since revenue is steady, looks at costs: a bigger share of fixed costs or lumpy one-off spending. It names the number that would confirm it and asks for the cost split.
6An exhibit shows a target's sales growing 12% a year while its market grows 4%. What does it tell you, and what do you ask next?
What a strong answer does: Says the target is taking share, then asks where the share comes from (price, new stores, a rival's exit) and whether it can last, since the growth plan rests on it.
L.E.K.: commit to a course of action, but show flexibility and a willingness to rethink in the face of new data.
7You have sized the market for a new hospital software product. The CEO asks what to charge. Give your recommendation in thirty seconds.
What a strong answer does: Gives one pricing logic (the value to the customer against today's alternatives), one price range, the main risk and what it would test first, then stops talking.
8Should the fund buy the company at this price? You have two minutes.
What a strong answer does: Answers yes or no first, gives the two facts that decide it (how fast the market grows and whether the plan is achievable), names the key downside risk and the price at which its answer would change.
10A chart shows a material's share of a market falling from 42% to 27% over five years while the market grows from 14.2 to 18 billion. Did the material's sales fall?
What a strong answer does: Multiplies share by market size for both years (about 6.0 billion, then about 4.9 billion) before answering yes, instead of reading the share alone.
L.E.K.: questions about your professional background, your strengths and why L.E.K. specifically.
11Why L.E.K., and not a larger strategy firm?
What a strong answer does: Names something specific L.E.K. says about itself (its private equity and M&A work, shorter projects, the generalist associate model) and ties it to something you have done, in under a minute.
12Tell me about something you do outside work and why you enjoy it.
What a strong answer does: Tells a short story with a moment of choice in it and what it says about you; a Boston associate wrote that a question like this tested his storytelling.
L.E.K. gives approach questions and no answers on purpose. Work each case out loud before you open any worked solution, ours included. Source: L.E.K., read (opens in a new tab)
Skipping the restatement
L.E.K.'s first tip is to repeat the question and state your assumptions. Jumping into math without it is how you size the wrong market. Source: L.E.K., read (opens in a new tab)
Not sanity-checking the number
A London associate sized weddings as if each person had one alone. Check the result against something you know before you present it. Source: L.E.K., read (opens in a new tab)
Hedging at the end
L.E.K. asks you to commit to a course of action. Give one answer with a number, then show you would change it if the data did. Source: L.E.K., read (opens in a new tab)
Each arrow opens the source: L.E.K., read Nov 9, 2026.
An L.E.K. prep plan, day by day
The order follows L.E.K.'s own pages; the timing is our suggestion.
Days 1 and 2
Read L.E.K.'s own pages
Read the interview preparation page and the apply page, then check your invitation; for London, read the privacy notice for the online assessment and the academic screen.
One case a day: answer its five approach questions out loud and timed, write a one-line answer with a number, then compare with our worked solutions and redo the step you missed.
How should I prepare for the L.E.K. Consulting case interview, and which free resources should I use?
Start with L.E.K.'s interview preparation page: work its three published cases (a brainteaser, Brewery Profits and Large Pharma Co.) cold, since L.E.K. gives approach questions but no answers, and our L.E.K. practice cases page works all three. Then train what L.E.K. names: quantitative and strategic cases, and experiential questions about your background. On Road to Offer a free account includes 1 full AI-graded case, such as iPhone X-Change, our L.E.K.-style case that sizes the US used-device market; Dunmore Cargo Bikes (market sizing) and Velmont Capital (private equity acquisition) are worked cases with a model answer for every question and need no account; market sizing, case math and chart drills cover the numbers. Firm-style cases are practice cases written for Road to Offer or adapted from university consulting club casebooks, not the firm's own cases.
Where can I practice L.E.K. Consulting-style case interviews for free?
On Road to Offer, iPhone X-Change is an L.E.K.-style case you run out loud with an AI interviewer or step by step; your first full case is free with a free account, no card. Dunmore Cargo Bikes and Velmont Capital are free to read with a model answer for every question, no account. L.E.K.'s careers site has its own three case examples, and our L.E.K. practice cases page works them end to end.
What practice cases does L.E.K. Consulting publish, and how should I prepare with them?
Three, on L.E.K.'s interview preparation page: A Brainteaser (how many planes flying the other way you pass between New York and Los Angeles), Brewery Profits (why one of two similar brewers has volatile profits, and what its CEO should do) and Large Pharma Co. (size the market for a daily baldness pill, then describe how you would price it). Each comes with five approach questions and no answer. Work each one out loud and timed, as if an interviewer were listening, and end with a one-line answer and a number. Then compare it with a worked solution, such as our L.E.K. practice cases page, and redo the step you missed. Use L.E.K.'s seven tips as the checklist: restate the question, plan an approach, stick to it, ask for data, share hypotheses and commit to an answer.
Does L.E.K. have an online test or a written case?
In some offices. L.E.K.'s recruitment privacy notice names Applied as the online assessment provider for certain London (UK) vacancies, and a London associate described online psychometric and math exams on L.E.K.'s blog in 2023. A written case is a candidate report, most often from Boston (US) final rounds; L.E.K.'s own pages do not mention it. L.E.K. says only that its process differs by region and level, so follow your invitation. Road to Offer has no L.E.K. test simulator; the closest practice is our case math and chart drills.
How many interview rounds does L.E.K. have?
L.E.K. says several, and that its process differs by region and by the level you apply for. A Boston (US) associate wrote on L.E.K.'s blog in 2022 that the first round was two interviews, one case strategy and one more quantitative, followed by interviews with partners and principals. A London (UK) associate described online tests before face-to-face case and fit interviews. Candidates report a written case added to some final rounds.
What does the L.E.K. fit interview cover?
L.E.K. calls it the experiential interview: questions about your professional background, your strengths and why you want consulting and L.E.K. specifically, run alongside the case rounds. Prepare a specific "Why L.E.K." answer and two or three stories with numbers in them, and say them out loud; Road to Offer's L.E.K. fit practice asks the questions with follow-up probes, 1 session free with a free account.
Is the L.E.K. case interview candidate-led or interviewer-led?
L.E.K.'s pages don't say, and candidate reports differ. Its seven tips read as if you drive the case: restate the question, devise an approach and stick to it, ask for the information you need and commit to an answer. Practise opening with your own structure, and also answering one directed question at a time with a number.
How long is an L.E.K. case interview?
L.E.K. doesn't say. Candidates report first-round interviews of about 30 minutes each with two different interviewers, part of it background and fit, and longer cases plus a written case of about an hour in some final rounds. L.E.K. says its process differs by region and by the level you apply for, so your invitation is the source to trust.
Does L.E.K. ask market sizing questions?
Often enough to train them first. L.E.K.'s Large Pharma Co. example asks you to estimate a market and then price the product, and a London (UK) associate wrote on L.E.K.'s blog in 2023 that one of his interviews was a market sizing for weddings, where the interviewer cared more about his method than the figure. L.E.K. describes its due diligence for investors as starting with the market landscape, so expect the estimate to feed a decision.
What is the answer to the L.E.K. brainteaser?
L.E.K. publishes none. Worked on one clock, you are in the air from noon to 5 p.m. New York time, and every plane that leaves Los Angeles between 7 a.m. and 5 p.m. New York time is airborne at some point during your flight: eleven planes, or nine if you leave out the one landing as you take off and the one taking off as you land. What it tests is turning two time zones into one clock and naming the endpoints, not the number.
What are L.E.K.'s academic requirements in London?
L.E.K.'s recruitment privacy notice says applications for consulting roles in its London offices are screened automatically against a minimum of a 2:1 undergraduate degree and AAB at A level, with an A in Maths if taken, plus fluent English, or equivalent. Applications that miss it get an automatic email, and you can ask for a person to review the decision. The same notice names Applied as an online assessment provider for certain London vacancies. It was last updated in January 2020, so check your vacancy.
Can I apply to more than one L.E.K. office?
Not in the same year. L.E.K.'s apply page says candidates can submit an application to only one of its global offices per year, through its Oleeo application system, and that recruiting seasons vary by region. Choose the office whose sectors and language you can talk about, and check its season before you apply.
