Serviceable Obtainable Market (SOM)

SOM

Serviceable Obtainable Market (SOM) is the realistic portion of the Serviceable Addressable Market a company can capture within a defined time horizon, typically 1–3 years, given its current resources, team, and go-to-market velocity. SOM is the only market sizing number that should directly anchor revenue projections in a fundraising deck — it is what you are actually going after.

formula.sh

SOM = SAM × Realistic Market Share Capture Rate

> SAM: your serviceable addressable market (the filtered, reachable universe)
> Market Share Capture Rate: the percentage of SAM you can realistically win in 1–3 years based on current growth rate and team capacity
> Cross-check: SOM should match or slightly exceed your 3-year ARR projection — if they diverge significantly, one is wrong
> Typical SOM is 1–5% of SAM for early-stage startups; higher shares require justification

example

example.sh

SAM is $714M. You are currently growing at 80% YoY. At current ARR of $600K and this growth rate, you project $3.8M ARR in 3 years.

$3.8M projected ARR ÷ $714M SAM = 0.53% SAM capture in 3 years

→ SOM = $3.8M ARR (0.53% of SAM) — a credible and conservative 3-year target

why it matters

SOM is where market sizing meets revenue reality. It is the number that ties your TAM/SAM narrative to the financial model investors will stress-test. Founders who cannot explain how their SOM maps to their 3-year revenue projection either do not understand their market or are using market sizing numbers as decoration rather than planning inputs.

SOM also forces a bottoms-up validation of your go-to-market capacity. If your SOM requires closing 500 enterprise accounts per year but your sales team can handle 50, the number is wrong. A rigorous SOM calculation should be derived from your current sales cycle length, deal size, and team size — then validated against the market share percentage it implies.

common mistakes

✗Setting SOM as a round percentage of SAM (e.g., "we plan to capture 5% of SAM") without deriving it from operational capacity — investors see through this immediately

✗Making SOM so conservative that it implies a business not worth funding — if 3-year SOM is $800K ARR, the return profile is challenging for institutional investors

✗Not tying SOM to hiring plans — if achieving SOM requires 10 salespeople and you plan to hire 2, the math does not work

pro tips

✓Derive SOM from your current conversion rates and growth trajectory, then cross-check it against SAM percentage — the cross-check is how investors will audit it

✓Show the monthly or quarterly milestones between today and SOM — the roadmap is as important as the destination number

✓If SOM implies a market share above 5%, explicitly address competitive dynamics: why can you capture that share versus incumbents?

the mrrsucks take

Your SOM is $400M. That is 56% of your SAM captured in 3 years by a team of 4. The only company that has ever captured 56% of a market in 3 years is the one that built the market. You are not building the market. You are building a Notion template tool for freelancers.

faq

What percentage of SAM is a realistic SOM for early-stage SaaS?+

For seed and Series A companies, 0.5–3% of SAM over 3 years is credible. Higher percentages are defensible only with exceptional growth rates, strong network effects, or evidence of category-creating potential.

Should SOM match my financial projections exactly?+

They should be consistent. If your 3-year revenue projection and your SOM imply different market share numbers, investors will flag the inconsistency. Build them together using the same assumptions.

Does SOM become irrelevant once you are Series B+?+

It evolves rather than becoming irrelevant. At Series B, investors focus more on your current market share, competitive position, and expansion TAM. SOM transitions from a planning input to a retrospective validation of your early forecasts.

SAM explained›TAM explained›

related metrics

./install-the-daemon

$9. 365 roasts. one public endpoint of pure shame.