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TAM / SAM / SOM Calculator

TAM / SAM / SOM Calculator

TAMTotal Addressable Market
$1.0B
Market Sizing
Size your market the way investors expect to see it. Pick a method to compute TAM, then narrow to your serviceable and obtainable slices.
Your Market Stack
TAM SAM $250M SOM $25M

Total Addressable Market (TAM)

Three ways to size the maximum revenue opportunity. Bottom-up is often investor-preferred - top-down is best used when you can defend the source and segmentation.

#
Realistic buyers in your segment & geography.
$
Average annual contract value or ARPU.
Formula TAM = customers × ACV
Example A vertical SaaS company targeting 20,000 verified buyers at $4,800/yr per buyer = $96M TAM. Replace with sourced counts for your segment.

Serviceable + Obtainable Slices

Narrow your TAM down to what's actually within reach today. Two filters: what your product can serve (SAM), and what you can realistically capture in the next 3–5 years (SOM).

25%
Filter for product fit, geography, audience constraints. Example: if only 6,000 of 20,000 verified buyers meet your size, geography, and workflow criteria, SAM is 30% of TAM.
10%
Realistic market share in 3–5 years given competition, GTM resources, and sales cycle. Anything above ~25% is aggressive territory and will get questioned.
Your Narrowed Slices
SAMServiceable Available Market
$250M
SOMServiceable Obtainable Market
$25M
Disclaimer

Disclaimer: This is a starting point, not professional advice. Use it to frame the conversation, then validate the assumptions with real data and qualified advisors before making decisions.