Serviceable obtainable market (SOM)
In short
Serviceable obtainable market (SOM) is the portion of your serviceable available market that you can realistically capture in a defined period, usually one to three years. It is the most conservative of the three market-size figures.
Where total addressable market shows the theoretical ceiling, SOM is a plan. It is limited by headcount, marketing budget, product readiness, and how hard competitors defend their customers. For this reason SOM is the number that should tie to your revenue target.
How SOM fits with TAM and SAM
The three figures nest inside each other. TAM is everyone who could use your product. SAM is the part you can serve with your current product, pricing, and geography. SOM is the part of SAM you can actually win.
- TAM: All demand for the product category.
- SAM: The segment you can reach and serve today.
- SOM: The share of SAM you can win in the planning period.
How to estimate SOM
Bottom-up from capacity
Start with what your team can do. Count reps, how many opportunities each can work per quarter, your win rate, and your average deal size. Multiply them out.
Say a team has 6 reps who each close 8 deals a year at 20,000 in annual value. That is about 960,000 in new annual revenue, and it is a defensible SOM for the year if enough qualified accounts exist to feed it.
Top-down from market share
Take SAM and apply a share you think is achievable, based on competitor strength and your past traction. This is quicker but easier to inflate, so use it as a cross-check, not the main method.
Using SOM in planning
- Quota and hiring: If SOM is smaller than the revenue goal, you need a bigger SAM, not more optimism.
- Territory design: Split SOM accounts across reps so each territory holds enough winnable demand.
- Budget: Marketing spend should be sized to the accounts you can win, not to the full TAM.
Common mistakes
- Taking 1% of a huge market: "If we get 1% of TAM" is not a plan. It has no link to capacity or channels.
- Ignoring competitors: Accounts locked into long contracts are not obtainable this year.
- Never refreshing it: Update SOM each planning cycle with real win rates and pipeline coverage.
Serviceable obtainable market FAQs
What does serviceable obtainable market (SOM) mean?
SOM is the part of your serviceable available market that you can realistically win in a set period, usually one to three years. It reflects your sales capacity, budget, competition, and product readiness, so it is smaller than SAM and much smaller than TAM.
How do you calculate SOM for a B2B company?
The most reliable way is bottom-up: multiply the number of reps by the deals each can close per year and by your average deal value. Then cross-check against SAM to confirm enough qualified accounts exist to support that revenue.
What is a good SOM as a percentage of SAM?
There is no universal figure. It depends on how crowded the market is and how much capacity you have. Early-stage companies often capture a small share of SAM, so base your number on your own win rates and pipeline, not a rule of thumb.
Why do investors ask for SOM instead of just TAM?
TAM shows how large the opportunity could be, but SOM shows what you can actually capture and how. A credible SOM, built from sales capacity and channels, proves the team understands its go-to-market limits.
