SOM Calculator – Serviceable Obtainable Market
Estimate your serviceable obtainable market (SOM) — the share of your SAM you could realistically capture — with a market-share or sales-capacity method and a TAM → SAM → SOM funnel.
Written by the CalcBundle Research & Editorial Team · Reviewed by the Quality Review Team · Transparent formulas · results are estimates, not advice. · Updated
Serviceable obtainable market
Enter your SAM (serviceable available market) greater than zero.
What is a SOM calculator?
SOM — serviceable obtainable market — is the portion of your serviceable available market that you can realistically win in the near term. It is the most grounded of the three market-sizing numbers because it factors in competition and your actual capacity to sell.
How to calculate SOM
- Market-share method: SOM = SAM × expected market share %
- Sales-capacity method: (salespeople × customers each × conversion %) × revenue per customer
The calculator caps SOM at your SAM — you cannot obtain more than the market you can serve — and shows the full TAM → SAM → SOM funnel.
The TAM → SAM → SOM funnel
TAM is the whole market, SAM is what you can serve, and SOM is what you can obtain. Each narrows the one above it. Investors expect to see all three, with SOM built from realistic, defensible assumptions.
Example
With a $10M SAM and a realistic 5% market share, your SOM is $500,000. If you instead model it bottom-up from your sales team’s capacity, you may arrive at a similar or lower figure — using both is a good cross-check.
Why SOM is the number that earns credibility
Of the three market-sizing figures, SOM is the one that tells an investor whether you understand your own business. TAM and SAM describe the opportunity; SOM describes your grip on reality. A founder who presents a huge TAM but cannot explain how they will win their first few percent of it signals inexperience, whereas one who builds SOM from concrete sales capacity and conversion data signals exactly the opposite. This is why SOM should be the most conservative and best-evidenced number in your deck — it is where optimism meets execution, and where a plan either holds together or falls apart.
SOM is an estimate, not a promise
Treat SOM as a reasoned target range, not a guaranteed outcome — actual results turn on execution, competition and timing. Combine it with your startup valuation and unit economics such as your LTV:CAC ratio for a complete, defensible picture of both the size of the prize and your ability to win it.
Frequently asked questions
What is SOM (serviceable obtainable market)?
SOM is the share of your serviceable available market (SAM) that you can realistically capture in the near term, given competition, your sales capacity and go-to-market.
How do you calculate SOM?
Two methods. Market share: SOM = SAM × expected market share %. Bottom-up: customers you can acquire (salespeople × capacity × conversion) × revenue per customer. This calculator supports both and caps SOM at your SAM.
What is the TAM, SAM, SOM funnel?
It's a three-level view of market size: TAM (the whole market), SAM (the part you can serve), and SOM (the part you can realistically obtain). Each is a subset of the one above it.
Is SOM a guarantee of revenue?
No. SOM is an estimate of what you could obtain under reasonable assumptions — it is not a forecast or a guarantee. Actual results depend on execution, competition and market conditions.
What market share is realistic for SOM?
For a young company, realistic near-term market share is usually low single digits, and often well below 1% in a large, competitive market. Founders routinely overestimate this, assuming they can take 10% or 20% within a couple of years. A credible SOM leans on defensible evidence — your actual conversion rates, sales capacity and the share incumbents already hold — rather than an aspirational percentage. It is far better to present a modest SOM you can beat than an ambitious one you will miss.
Should SOM be built top-down or bottom-up?
Bottom-up is generally more convincing for SOM, because it ties the number to something you control — how many salespeople you have, how many prospects each can work, your conversion rate, and revenue per customer. The market-share method (a percentage of SAM) is a useful cross-check, but on its own it can hide unrealistic assumptions. When the bottom-up and market-share estimates roughly agree, you have a SOM you can defend; when they diverge, one of your assumptions needs another look.
How does SOM connect to my revenue forecast?
SOM is the ceiling your near-term revenue forecast should sit under, not the forecast itself. A sound financial model builds revenue bottom-up from real pipeline and conversion assumptions, then checks that the total stays comfortably within SOM. If your forecast exceeds your SOM, either the forecast is too optimistic or your SOM was understated — either way, the mismatch is a signal to revisit the assumptions before anyone relies on the numbers.
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Disclaimer. This calculator provides estimates for informational purposes only. Results are based on the information you enter and the assumptions used by the calculator. Actual financial, tax, business valuation, lending, marketplace or investment outcomes may differ. Consider consulting a qualified professional for decisions involving significant amounts of money. Market-size calculations are estimates and depend on the assumptions and data used. SOM is not a guarantee of revenue.