TAM, SAM and SOM

What TAM, SAM, SOM actually means

These three figures size a market from the outside in. Total addressable market is every dollar that would be spent if the company reached everyone. Serviceable addressable market narrows to the segments the product and go-to-market can actually serve. Serviceable obtainable market is the realistic near-term share given competition and capacity. The third number is the only one anyone should plan against.

Worked example

A workflow tool for dental practices calculates a 4,000,000,000 dollar TAM across all small business software, a 340,000,000 dollar SAM covering dental practices in its three launch countries, and a 12,000,000 dollar SOM based on the segments it can reach with current sales capacity over three years. The first number opens the conversation. The third one sets the plan.

Why the board cares

Boards discount top-down market sizing almost automatically, because a large TAM built from an analyst report is easy to produce and proves very little. A bottom-up SOM built from actual account counts, realistic win rates and current capacity is the number that earns credibility, and it is the one that anchors any serious go-to-market plan.

Common mistakes

• Presenting a TAM built top-down from an industry report with no bottom-up validation.
• Confusing SAM with SOM, which sets targets against a market the company has no capacity to serve.
• Never revisiting the numbers after the product or the market has moved.

Related terms

• Share of Voice (SOV)
• Annual Contract Value (ACV)
• Win Rate
• Pipeline Coverage Ratio

Back to the full marketing glossary