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TG3 SaaS/Tools/TAM SAM SOM
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TAM SAM SOM calculator. Size the market you can really win.

A free TAM SAM SOM calculator that sizes your market in three nested circles. The honest number is SOM, the slice you can realistically win, not the giant TAM that impresses nobody.

The calculator

TAM SAM SOM, live.

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Your SOM
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This calculator runs entirely in your browser. Nothing you enter is sent anywhere or stored. It is a quick estimate, not financial advice.

Why it matters

What TAM SAM SOM actually measures.

TAM SAM SOM sizes your market in three nested circles. TAM is everyone who could ever buy the category. SAM is the slice your product and model can serve. SOM is the portion you can realistically win in the near term. The gap between them is where most pitch decks quietly lie.

The useful number is SOM, not TAM. A huge TAM impresses no one who has seen a hundred decks. A defensible SOM, with a clear reason you can reach and win it, is what separates a real plan from a fantasy.

How to use it

Using TAM SAM SOM honestly.

Build it bottom-up, not just top-down. Top-down sizing, taking a giant market and assuming you capture 1 percent, flatters everything. Bottom-up, counting real accounts you can reach and a believable win rate, keeps you honest.

Revisit it as you learn. Early SOM estimates are guesses. As real win rates and reachable-account data come in, tighten the percentages. A market size you never update is a market size you no longer believe.

Common questions

What people ask about the TAM SAM SOM calculator.

What is a TAM SAM SOM calculator?+

A TAM SAM SOM calculator sizes your market in three layers. It takes your total addressable market, applies the share your product can serve to get SAM, then the share you can win to get SOM.

What is the difference between TAM, SAM and SOM?+

TAM is everyone who could buy the category, SAM is the part your product and model can serve and SOM is the portion you can realistically capture in the near term.

Which number matters most?+

SOM. A large TAM is easy to claim and impresses no experienced investor. A defensible SOM, with a clear path to reach and win it, is what counts.

Should I size top-down or bottom-up?+

Both but trust bottom-up. Counting real reachable accounts and a believable win rate is far more honest than assuming you capture a percentage of a giant market.

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