How would you go about this market sizing question: 'How many barbershops/hairdressers are there in the UK?'

case interview preparation estimation market sizing market estimation Market sizing
New answer on Dec 21, 2020
5 Answers
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Anonymous A asked on Dec 18, 2020


I was practicing market sizing questions, and came across this question:

How many barbershops/hairdressers are there in the UK?

I went about about this question through these steps:

1) Population (65m)
2) Working age adults (I estimated this to be 33m as I made the assumption that 0-19 and 60-80 do not work and/or they do but at negligible rates)
3) Proportion of working age adults that are hairdressers/barbers (I estimated 1%)
4) Average number of workers in a barbershop/hairdressers (I estimated 10)
5) Divide the total no. of hairdressers by average number of workers in a barbershop/hairdresser

This got me to an answer of 33,000.

I would be grateful for any suggestions as to how to approach this question and whether my approach can be improved!

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Content Creator
updated an answer on Aug 26, 2021
MBB | 100% personal interview success rate (8/8) and 95% candidate success rate | Personalized interview prep

Hi there,

Sorry to be so blunt, but you already failed at step 2.

Remember, market sizing isn't about coming to the exact right answer insomuch as it's about assessing your ability to have structured thinking and ability to think reasonably. You didn't do this :/

Wrong approach - You cannot just randomly guess what % of your total pop is hairdressers in order to figure out how many hairdressers are in the UK. This is not breaking down a problem into logical segments in order to make more reasonable assumptions. You literally just said "ah, maybe x% multiplied by the total population!"...that's not strategic thinking...sorry!

Ok, so, how to we fix this? Well, we have to look at what ways I can break this down into more reasonable steps/assumptions!

So, let's thinking about:

  1. # of people in the UK
  2. # of haircuts per person per year
    1. Think monthly
    2. Break down population into reasonable segments that affect frequency of haircuts
  3. Throughput of an average barbershop/hairdresser
    1. Think hourly and expand out
  4. Calculate # of shops needed (by # of haricuts and throughput)

And viola! Much more reasonable to make these kinds of assumptions!

Hope this helps, but feel free to message with any questions!

Take a look here for additional practice!


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Content Creator
replied on Dec 20, 2020
McKinsey | Awarded professor at Master in Management @ IE | MBA at MIT |+180 students coached | Integrated FIT Guide aut


Like the approach!

You can also think it by population who needs a haircut, extrapolating by the number of barbrshops you konw there are in an area, etc.

However, yours works
​Hope it helps!



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Content Creator
replied on Dec 19, 2020
McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School


I would rather go with demand:

  1. Population (men, women, age split)
  2. Frequency of haircuts by group
  3. Average capacity and occupancy of a barbershop
  4. Number of barbershops by dividing total demand and supply of one barbershop (adjusted by av occupancy)


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Content Creator
replied on Dec 19, 2020
Accenture, Deloitte | Precision Case Prep | Experienced Interviewer & Career Coach | 15 years professional experience


I think good first attempt. But there are some weaknesses in your approach:

  1. Why 1% are hair dressers- how do you back that assumption?
  2. Think about men or women's salon/hair dressers/barber
  3. Think about hours of operations, number of people getting services in a day etc

Have a look at these threads for a similar question & solution:

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Content Creator
replied on Dec 21, 2020
Ex-Mckinsey|Certified Career Coach |Placed 500+ candidates at MBB & other consultancies

Hi there,

Interesting question! Thank you for sharing.

I agree that it makes more sense to build your reasoning starting with the demand.

Don't forget that haircut is not the only reason people go to hairdressers.

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Ian gave the best answer


Content Creator
MBB | 100% personal interview success rate (8/8) and 95% candidate success rate | Personalized interview prep
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