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?

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

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

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

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. 

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