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TAM SAM SOM Calculator

Updated April 17, 2026 · Financial Health · Educational use only ·

Market opportunity sizing.

Calculate TAM, SAM, and SOM for market sizing and investor pitches. Enter addressable market tam and serviceable available sam for an instant result.

What this tool does

This tool calculates Total/Serviceable/Obtainable market sizes for business plans and pitches.


Enter Values

Formula Used
Total addressable market
Serviceable available %
Obtainable capture %

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Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

TAM/SAM/SOM calculator estimates market opportunity at three levels. TAM (Total Addressable Market): total demand if 100% market share globally. SAM (Serviceable Available Market): segment your business can realistically reach. SOM (Serviceable Obtainable Market): realistic capture in 3-5 years given competition.

Example: TAM 10B (global cloud storage market). SAM 15% = 1.5B (-speaking SMB segment). SOM 2% = 30M (realistic 5-year capture given competitors). Investors expect founders to know all three - TAM shows ambition, SOM shows realism.

Methods: top-down (start with industry data, narrow), bottom-up (start with unit economics × addressable customers), value theory (price × number of users who'd pay). Bottom-up most credible for VCs. Beware inflated TAMs - 'we're targeting the 100B fitness market' is meaningless if you're a yoga app.

Run it with sensible defaults

Using total addressable market of 10,000,000,000, serviceable available of 15%, obtainable capture of 2%, the calculation works out to 30,000,000.00. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Total Addressable Market (TAM), Serviceable Available % (SAM), and Obtainable Capture % (SOM) — do not pull with equal force. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

How the math works

SAM = TAM × SAM%. SOM = SAM × SOM%. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

What to do with a low result

A disappointing result is information, not a judgement. Pick the single input that dragged the figure down most and focus the next quarter on that one factor. Breadth-first improvement rarely works; depth-first on the worst input usually does.

What this doesn't capture

The score is a composite of the inputs you provide. Life context — job security, family obligations, health, housing — doesn't appear in the math but shapes the real picture. Use the number as a prompt, not a verdict.

Example Scenario

TAM £10,000,000,000 £ × 15% SAM × 2% SOM = $30,000,000.00 obtainable.

Inputs

Total Addressable Market (TAM):10,000,000,000 £
Serviceable Available % (SAM):15
Obtainable Capture % (SOM):2
Expected Result$30,000,000.00

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

SAM = TAM × SAM%. SOM = SAM × SOM%.

Frequently Asked Questions

How to calculate TAM?
Three methods: (1) Top-down: industry research × your subset (e.g., Gartner reports global SaaS market = £X). (2) Bottom-up: addressable customers × ARPU. (3) Value theory: hours saved × $/hour × user count. Bottom-up most defensible for investors.
What SAM % is reasonable?
Depends on geographic, language, and segment focus. -speaking SaaS targeting SMBs: 15-25% of global TAM. Single-country B2B: 3-7%. Niche vertical (e.g., dental software): 1-3%. Be specific about exclusions: 'we exclude financial services, and 1-person businesses'.
What SOM % is realistic?
5-year horizon: 1-5% of SAM is typical for early-stage startup. 10% is aggressive (requires market leadership). 20%+ requires winner-takes-all dynamics. VCs scrutinise SOM more than TAM - if your SOM implies dominating the market, expect tough questions on competitive moats.
Why investors care?
Determines venture-scale: 1B TAM rarely justifies VC investment (need 10B+ for unicorn outcomes). SAM shows you understand your specific market. SOM shows realism. Founders who quote TAM but not SOM signal naivety. Pitch should always have all three.

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