Market size sizing for a pitch. The TAM SAM SOM Calculator takes total addressable market (tam), serviceable share of tam (your segment and geography), obtainable share of sam in the planning horizon and returns serviceable obtainable market (som) plus serviceable addressable market (sam), som as a share of tam. Results update as you type, and the formula is shown under the result so you can repeat it in your own spreadsheet.
Startup metrics are about the efficiency of growth: how much it costs to win and keep customers, how fast recurring revenue compounds, and how long the cash lasts. Investors read these numbers before they read the pitch. Use the worked example below to check the maths against your own figures.
How the TAM SAM SOM Calculator works
TAM is everyone who could buy, SAM the part you can actually reach with your product and geography, SOM the slice you can realistically win in a few years. Investors care about SOM and how you got there.
Worked example
With the example values (total addressable market (tam) of $5,000,000,000, serviceable share of tam (your segment and geography) of 20%, obtainable share of sam in the planning horizon of 5%), the serviceable obtainable market (som) is $50,000,000.00; serviceable addressable market (sam) $1,000,000,000.00, som as a share of tam 1%. Change any figure above and the result updates immediately; use Copy results to paste the summary into a note or email.
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Frequently Asked Questions
How is serviceable obtainable market (som) calculated?
SAM = TAM × serviceable share; SOM = SAM × obtainable share.
Which figures do I need?
Total addressable market (tam), serviceable share of tam (your segment and geography), obtainable share of sam in the planning horizon. Take them from the same period and the same set of accounts or reports so the ratio is consistent, and check the example values as a guide to the units expected.
What do investors consider healthy?
Common benchmarks: LTV:CAC above 3, CAC payback under 12–18 months, net revenue retention above 100%, monthly churn under 2% for SMB and under 1% for enterprise, and at least 12–18 months of runway.
