Do you think is a good idea to bring a calculator?

I'm preparing to McK coming next week
New answer on Sep 07, 2021
9 Answers
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Anonymous A asked on Sep 06, 2021

Hello everyone! Since interviews are virtual I was thinking on using a calculator since most of the time due to nerves I made mistakes. Is it a bad idea? 

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Florian
Expert
Content Creator
replied on Sep 06, 2021
Highest-rated McKinsey coach (ratings, offers, sessions) | 500+ offers | Author of The 1% & Consulting Career Secrets

Hey there,

It's not a good idea. It is not allowed for case interviews.

Even if you try to do it covertly because the interviewer does not see what is on the table in front of you, they would actually spot it due to

  • the way you look
  • the sound of the keys
  • unnaturally fast results

Rather focus on number drills and getting comfortable with quick mental math. PrepLounge has a good tool for that.

Cheers,

Florian

 

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michelle
Expert
replied on Sep 06, 2021
Creative Background to McKinsey. I help non-traditional backgrounds with defining your story and case prep

Haha, I would be very amused if an interviewer brought a calculator. Don't do it. The interview is to assess how you would act in front of a CEO level client. 

You CAN mess up the math. I did and got into McKinsey just fine. 

Also, you don't need to do mental math. Its perfectly OK to write out the math, and walk the interviewer through it. Make it easy to follow, slow and steady, and you'll be fine. Try to go fast and impress them, and it's a risk.

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Adi
Expert
Content Creator
replied on Sep 06, 2021
Accenture, Deloitte | Precision Case Prep | Experienced Interviewer & Career Coach | 15 years professional experience

Not a good idea am afraid. So avoid doing this.

I know its frustrating when the calculator was invented for a good reason! I personally feel its only a matter of time when this rather lame practice of not allowing calculators will be discontinued. We are using AI/ML in the real world but discourage candidates from using calculator in interviews. Yes, there is supporting argument for that but its time for a change.

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Erica
Expert
replied on Sep 06, 2021
Ex-McKinsey / 100% offer rate / LBS / Principle driven / Real case/ If you get the interview, you should get the offer!

Hi there. I would advise against it, for following reasons:

- Actual number calculation is just a small part of your maths questions. The biggest and most important step is to lay out the right structure (for maths) and formula. And based on experience, it is quite rare, especially for MBB, that you get a complicated calculation. In most cases, actual number calculation is quite simple and the difficult part is always the upfront maths structure.

- As consultants, being able to do a quick back of envelope calculation is a very basic requirement. Even though the interview is virtual, you bear the risk of the interviewer finding out about your calculator, which demonstrates your lack of skill and confidence.

Instead of bringing a calculator, I suggest you spend sometime doing some mental maths drill exercises. This will largely improve your calculation speed and accuracy. 
 

Hope this helps! All the best with your upcoming interview :)

 

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Ian
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Content Creator
replied on Sep 06, 2021
#1 BCG coach | MBB | Tier 2 | Digital, Tech, Platinion | 100% personal success rate (8/8) | 95% candidate success rate

Hi there,

Honestly, I think it's a bad idea. It's quite risky and again the rules/protocols…breaking these rules may serve you well in a given moment, but in aggregate they'll only bring you down!

Practice your math here on Preplounge! https://www.preplounge.com/en/mental-math

Feel free to reach out for other tips on ramping up your fast math.

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Antonello
Expert
Content Creator
replied on Sep 06, 2021
McKinsey | NASA | top 10 FT MBA professor for consulting interviews | 6+ years of coaching

Hi!

Don't bring a calculator. Mental math is an important skill assessed by the interviewers.

I recommend you speak loud while doing your math. This helps you avoid mistakes and the interviewer to remain engaged.

Hope this helps.

Best,

Anto

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Calvin
Expert
replied on Sep 06, 2021
Experienced interviewer | Roland Berger Project Manager| Cambridge University | Super intuitive approach

Hi there,

It's not a good idea. Even in an online interview, the interviewer can spot it if you are using a calculator. I actually once caught an interviewee trying to use a calculator…

Your quantitative skills and "being comfortable with numbers" are important to succeed as a consultant. There are tools on the internet to help you with this. Let me know if you need support on this.

All the best with your upcoming interview(s) :)

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Sofia
Expert
replied on Sep 06, 2021
Top-Ranked Coach on PrepLounge for 3 years| McKinsey San Francisco | Harvard graduate | 6+ years of coaching

Hello,

Don't do this - you are explicitly prohibited from using a calculator in interviews, and, as other experts here have pointed out, interviewers can often tell when a candidate is doing so (e.g. they look down or to the side, get results very fast, different sound of keys tapping, etc.). It is a very large risk. If mental math is an area you don't feel particularly comfortable with, work on improving that instead.

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Agrim
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Content Creator
replied on Sep 07, 2021
BCG Dubai Project Leader | Learn to think like a Consultant | Free personalised prep plan | 6+ years in Consulting

Bad idea.

The math in case interviews is many times easier done on paper than on a calculator.

Further, the interviewer is testing your casing skills, not plain arithmetic.

Finally, if you feel you are not good at math - best to get some practice under the belt.

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Florian gave the best answer

Florian

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