Serviceable Addressable Market

What Serviceable Addressable Market means in practice

SAM applies the constraints TAM deliberately ignores. If your product is English-only, non-English buyers leave the number. If you sell self-serve, enterprises requiring procurement and security review leave it. If regulation limits you to one jurisdiction, everyone outside it leaves. What remains is the market your business as currently designed can actually address.

The gap between TAM and SAM is diagnostic rather than disappointing. A SAM that is a tiny fraction of TAM tells you most of the theoretical opportunity is locked behind constraints — and each constraint is a strategic choice you could revisit. Adding a language, a compliance certification or a sales motion converts locked TAM into SAM, and knowing which unlock is largest is genuinely useful roadmap information.

Because SAM depends on how your business is built rather than on the market alone, two companies in the same category can have very different SAMs from an identical TAM. That is a feature of the metric, not a flaw.

How it is calculated

Worked example

The £15.1m UK accounting-compliance TAM, narrowed by product constraints.

• Start from TAM: £15.1m (4,200 practices × £3,600).
• Product integrates only with Xero, used by roughly 55% of that segment: 2,310 practices.
• Self-serve onboarding excludes the ~15% requiring bespoke procurement: ~1,964 practices.
• SAM = 1,964 × £3,600 = £7.1m per year.

Takeaway: SAM is under half of TAM, and the single biggest constraint is the Xero-only integration. That makes adding a second accounting integration a quantified roadmap decision rather than a guess.

Common mistakes

• Treating SAM as an arbitrary percentage of TAM instead of deriving it from named constraints.
• Forgetting that SAM changes when the product changes — it is not a fixed property of the market.
• Excluding buyers who are merely hard to reach rather than genuinely unreachable; difficulty belongs in SOM.
• Applying overlapping constraints twice and understating the result.

Related tool: TAM/SAM/SOM calculator.

Related terms

• Total Addressable Market — Total addressable market (TAM) is the total annual revenue available if a product achieved 100% market share of everyone who could conceivably buy it — the theoretical ceiling, not a realistic target.
• Serviceable Obtainable Market — Serviceable obtainable market (SOM) is the share of your serviceable addressable market you could realistically capture within a defined period, given your budget, team, distribution and existing competition.
• Go-to-Market Strategy — A go-to-market strategy is the plan for reaching and selling to a specific customer segment — covering who you target, the channels you use, how you price, and the sales motion that converts interest into revenue.

Last reviewed 8 August 2026