Guesstimates and market sizing: the guide
How to estimate any quantity from almost nothing: clarify what is asked, build a short formula top-down or bottom-up, segment where it matters, choose assumptions that fit the region, and sanity-check against a real anchor.
Last reviewedWhat strong candidates can do
- Clarify what is being estimated before building anything
- Choose between top-down and bottom-up, and check one against the other
- Pick assumptions that fit the region and defend them out loud
- Sanity-check against an outside anchor and stay calm when challenged
Common questions
What is a guesstimate or market-sizing case?
How to estimate any quantity from almost nothing: clarify what is asked, build a short formula top-down or bottom-up, segment where it matters, choose assumptions that fit the region, and sanity-check against a real anchor.
How do you approach a guesstimate or market-sizing case?
Clarify exactly what is being counted, for which region and time period. Choose top-down or bottom-up, split the population into sensible segments, state each assumption out loud, and sanity-check the result against something you know.
What is the most common mistake in a guesstimate or market-sizing case?
Jumping to a number without a structure, or using one average for groups that behave very differently.
Go deeper
The full lessons, worked examples, drills and a case simulator with automated feedback are in the platform. No sign-up is needed to start.