Define one customer unit
Choose accounts, users, transactions, locations, or another unit and use it consistently across the estimate.
Market sizing tool
TAM, SAM and SOM calculator
Build a transparent bottom-up market estimate from customer count, annual revenue, serviceability, and realistic initial reach.
- Free to use
- Runs in your browser
- No details saved
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Enter your assumptions
Use a clearly defined customer segment and cite the source for every input in external materials.
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Use a clearly defined customer segment and cite the source for every input in external materials.
How to use this tool
Use the output as a decision prompt
TAM describes the full annual revenue opportunity under your definition. SAM narrows it to customers your product and operating model can serve. SOM estimates a credible initial share of that serviceable market over a stated period.
Bottom-up estimates are more useful when each input can be explained: who qualifies as a customer, how many exist, what they would pay each year, what limits serviceability, and what sales capacity supports the obtainable share. Avoid presenting a large industry report as if all spending belongs to your product.
Method and interpretation
What the calculation is designed to show
Use revenue, not economic value
The annual input should reflect what your company earns from one customer, not the total value the customer receives.
Explain every constraint
Geography, regulation, language, product scope, integrations, channel capacity, and implementation can all reduce SAM and SOM.
Useful applications
When this tool can help
Revisit the calculation when assumptions or evidence change. Keep the inputs with the result so another founder or adviser can understand the reasoning.
- Build a bottom-up pitch estimate
- Compare pricing scenarios
- Define an initial market wedge
- Prepare investor assumptions
- Plan sales capacity
- Challenge an inflated market claim
Questions and limitations
Understand what the result cannot decide
What is the difference between TAM, SAM, and SOM?
TAM is the total annual revenue opportunity under your broad market definition. SAM is the part your current model can serve. SOM is the realistic portion of SAM you may capture within a defined period.
Should SOM be a percentage of TAM?
This calculator applies obtainable share to SAM because SOM should reflect the market you can actually serve. Explain the period and operating assumptions behind the percentage.
Can I use this number in a pitch deck?
Yes as an estimate, provided you cite reliable sources, explain the calculation, state the date and scope, and avoid presenting assumptions as audited facts.
What if I have several customer segments?
Estimate each segment separately with its own customer count and annual revenue, then combine only segments that do not overlap.
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