Market

TAM, SAM, SOM: sizing your market realistically

TAM is the total market for your kind of solution, SAM the share your offer can actually serve, SOM the share you can realistically win in 3–5 years. Investors and lenders care least about the TAM and most about a credible, bottom-up calculated SOM.

Who serves that market today: competitor analysis in 5 steps →

From total market to your share

TAM100%

SAM38%

SOM8%

TAM: Total Addressable Market

Everyone who could theoretically buy your kind of solution. Example mobile bike repair: all bike repair and service in the US. The bicycle dealership and repair industry runs at about $8 bn a year, of which repair and service is the smaller share, call it $1.5–2 bn (estimate).

SAM: the part you can serve

Limited by your offer and region. Example: repairs in the Portland metro area, for customers willing to book online, perhaps $10–15 m per year.

SOM: what you can realistically win

Bottom-up from capacity: 2 mechanics × 6 repairs/day × 220 days × $75 average ≈ $200k per year. That is the number to plan with.

The SAM only narrows down once you know which group you serve: how to define your target audience in four steps →

Rule of thumb: state every number as a range with the assumption behind it ("6 repairs a day, assuming 45 minutes each plus travel"). A transparent estimate beats a precise-looking guess every time.

Frequently asked questions

Where do I get the numbers for TAM, SAM and SOM?

Free sources are enough to start: national statistics offices, industry associations, annual reports of listed competitors and simple arithmetic (number of target customers times annual spend). The transparent calculation behind the number matters more than the exact figure.

How big does a market need to be for an idea to be worth it?

It depends on the goal: a side business can work with a SOM of a few hundred thousand euros. If you seek venture investors, you usually need a TAM from around one billion euros, because funds depend on very large outcomes.

What is the most common mistake in market sizing?

Top-down wishful thinking: "The market is 50 billion, 1 percent is enough for us." Nobody gets 1 percent automatically. The credible route is the reverse: bottom-up, extrapolating from your own capacity and realistic customer numbers.