How many cases should i perform 100% correctly to feel confident for the interview if i already did 100% of the Mckinsey cases in their web page?

Question

I have done at least 10 cases, with some errors and have read A LOT of information about Mckinsey and their case interviews. However, i dont know how much cases should i be doing. I have done all the cases they have in their web page.

I have a Mckinsey interview pretty soon and i am extremely nervous and anxious about this. I think i dont even have enough time.

Answer 1

Hi there,

First of all, congratulations on the (presumed) invitation from McKinsey!

I would be happy to share my thoughts on your question:

First of all, I would highly advise you not to practice (exclusively) with the case studies published on the McKinsey website, as they are all a bit strange. Also, reading is really only helpful in the very beginning to understand the concept of case studies in general.
Moreover, I would advise you to work with an experienced coach like me to do a case study diagnostic to assess your current level of readiness. As the most experienced coach in terms of consulting, interviewing and coaching experience, I'd be more than happy to help you.

You can find more on this topic here: How to succeed in the final interview round.

If you would like a more detailed discussion on how to best prepare for your upcoming McKinsey pre-interview assessment and/or interviews, please don't hesitate to contact me directly.

Best,

Hagen

Answer 2

Hey,

It’s normal to feel nervous, but you’re on the right track! There’s no magic number of cases, but 15–20 well-practiced ones is a good benchmark, and with 10 completed—including McKinsey-specific ones—you’ve made great progress. Focus on quality over quantity; McKinsey values structured thinking, problem-solving, and clear communication more than perfect answers. Use your remaining time to refine weak areas (e.g., structuring, mental math), practice under pressure with a partner, and revisit McKinsey’s core principles like MECE and top-down communication. Aim for 2–3 more focused cases, review past mistakes, and prioritize rest to stay sharp. Trust your preparation—you’re closer than you think to being ready!

Happy to help you prepare - feel free to DM me :)

Best,
Evelina

Answer 3

Hi there!

There is no magic number. I’ve worked with people who have had an offer after 10 cases and others that fail after literally +100 cases.

One thing to notice is that the cases provided by McKinsey website are easier than what you’ll find during real interviews and they do not cover everything you may find, such as market sizing, market entry, etc.

I recommend you to try to postpone your interview by at least a month - just message HR and say that you would appreciate more time to prepare if possible. Worst thing they can do is saying “no”. That won’t hurt your chances btw.

After you’ve got this, I advise you to do some mocks with a very experienced person, may be a coach or not, to evaluate your skills in the case and experience interview so you can study in a smart way.

I would be happy to help you with your studying plan, send me a message if you think you could be benefited by professional guidance.

Best,

Mari

Answer 4

Push back the interview (if possible) if you're not ready. A few other thoughts:

Get to consistency, not perfection: You should feel like you can tackle complex cases, non-traditional topics/industries, and tricky quant and still come up with a clear and actionable recommendation.
Master all elements of the case (and fit): You need to solve the problem like a consultant would -- align on scope with incise, clarifying questions, start with a hypothesis-driven framework, propose/carry out analysis that gets you to nuanced insights (including dealing with exhibits), and prepare a CEO-level summary at the end. Getting to the answer with zero math mistakes isn't the measure of success. You need to show your problem-solving and communication skills very clearly.

It's normal to feel anxious, but don't let that paralyze you. Let's chat, so I can help you overcome the fear and craft a tailored plan to master the case.

Answer 5

Hey!

It’s super individual from my experience. I know people who did just one prep case and successfully interviewed at McKinsey, while others needed many more. Instead of focusing on a specific number, prioritize quality over quantity—make sure you’re learning from each case and improving consistently. Also, don't forget to prepare well for the personal fit part, which is crucial at McKinsey. Let me know if you need support!

Alessa

Answer 6

Hi, desk-based practice (ie working through cases by yourself) of around 10-15 cases is great. Especially to fine-tune structuring skills and mental maths. In addition though it is critical to do 3-5 mock interviews with a current / ex-consultant. Real-life mocks will test you under pressure, and will also give you a sense of the need to be nimble and think on your feet when asked challenging follow up questions. Happy to help of course.

Answer 7

Hey there,

The short answer and general principle for number of cases to practice: Practice until you feel comfortable, whatever that number may be. You should be chasing comfort, and not a number of cases

Also, I don't know about your personality type - but I'm not sure you'd ever be 100% confident.. Be careful about using 100% confidence as the marker to determine your readiness, as you might wait longer than you should to get the offer. I have had so many coachees that have prepared for McKisney Interviews in just 5 days and managed to pass and get offers (and whilst this is NOT ideal - my point is that you don't need 100% confidence.. just proper preparation)

So when you feel ready and can see you are consistently performing well and getting to the answers, that is the time to prepare!

McKinsey cases are my specialty. Please reach out if you'd like help preparing for these interviews

All the best

Answer 8

Hey,

10 cases is nowhere near enough to ace a case interview. You should aim to do at least 30 quality cases with peers and quality feedback, but the real number may be closer to 80-100. There's just a critical amount of data your brain needs to process and internalize (industry / problem types) before you are ready.

To progress quickly, I suggest you take an active learning approach (in the following order):

1. Getting coaching when you are a complete beginner to learn the basics;

2. After you've learned the basics, practice cases with peers to polish your case solving process and acquire understanding of a wide range of industries and problem types;

3. Before the interview, ask a few acting consultants to give you cases in a mock-interview format to assess your readiness.

Hope this helps.
Good luck!
Nick

Answer 9

Hey there,

It's not about x amounts of cases.

The key reason why candidates fail their case interviews and don't improve with practice is because they never learn the right approach and techniques to begin with. They might go through 30-40 cases, just repeating the same mistakes over and over again. There is often no strong baseline.
Make sure you understand and learn the basics for each part of the case (structuring, charts, math), which is
- A replicable step-by-step for each part of the case interview
- The right thinking techniques around the individual parts (e.g., what's a framework, what is evaluated, how can I ensure I think about it the correct way, what are some shortcuts to get to the answer quickly, etc.)
- Simple communication templates to help you communicate your insights as well as ask for data in the right way to drive the case forward
There are several approaches you can take, such as hiring a skilled coach, reading the right materials, or enrolling in relevant courses. For example, my book provides direct guidance tailored to modern case interviews. It covers all the essential points mentioned here, and more, while also offering a detailed preparation plan. You can find it on Amazon
Avoid generic advice and framework memorization approaches. This will only hurt your performance and waste a ton of time (why -> check out the first post here: https://www.preplounge.com/en/consulting-forum/how-goodrelevant-is-the-case-in-point-book-for-case-prep-1984)
Once you have that baseline it's time to practice and internalize the skills to create the right profile, polishing your strengths and lifting your weaknesses to a robust-enough level
Practice drills alone (structure, chart, math) and practice full cases with other excellent candidates that know the right habits and approach. It is crucial that you are practicing with really good peers, otherwise, it's a waste of time. Practicing drills on your own is a huge effectivity and efficiency booster since you can go over many more questions in a shorter amount of time compared to practicing with peers. Do both in parallel! You want to spend your time where it is most useful, e.g., if you struggle with math focus on math drills, etc.
Focus on quality over quantity. Doing 50+ cases does not mean much if you are not applying the right habits to score high and do a detailed debrief after every case to improve. You want to move from bad to good for your weaknesses and good to great for your strengths --> use the feedback from your previous experience and tailor your prep accordingly
Consider booking at least an initial coaching session to get a detailed and objective evaluation of your performance + learn the right habits for every case regardless of context and framework + get a tailored preparation plan out of the session that will set you up for an effective and efficient prep.
It does not hurt to focus a bit more on the relevant industries of your interviewer but chances are that not every case will be from that niche!
Don't forget the fit interview part (for McKinsey, that would be the PEI). Prepare answers for all the typical fit questions and stories (3-5 hours) and rehearse them a couple of times (5 hours)

All the best,

Florian

Answer 10

Hire a coach!

If you're worried, that's what coaches are for.

Now, it sounds like you read through those 10 cases, right? As in, nobody cased you.

In this case, you have technically done 0 cases.

You need to practice live with peers.

If you can get through several live peer cases with minimal errors, articulating yourself well, and doing it in approximately 20-25 minutes with a good score, then you are ready.

If you're worried about time and don'tn think you'll make it, a coach is your #1 time lever here.

Here's a crash course to help:

End-to-end case interview training – from beginner to advanced

And here's some reading to help:

The Most Common Pitfalls in Case Interview Preparation

Dos and Don'ts in a Case Interview

How to Shift Your Mindset to Ace the Case

Candidate-Led Cases: What to Expect With Example Cases

Answer 11

Quality, not quantity.

Doing something wrong and inefficiently many times will not make you improve or achieve a high level of performance.

Reading cases is really one of the most ineffective ways of practicing, you need to have live practice, if that's something you are not doing yet.

I would suggest trying to push back your interview until you feel ready.

Focus on skills and abilities, not on case count.