Total addressable market (TAM)
Total addressable market (TAM) is the revenue you would earn if every company that fits your offer bought it. In B2B outbound it is often counted from the bottom up: the number of accounts that match your ideal customer profile, times what one of them pays a year.
TAM, SAM and SOM
- TAM is every company that could use what you sell, anywhere, times what one of them would pay a year.
- SAM, the serviceable addressable market, is the part of TAM you can reach today: the regions you sell in, the languages you support, the segments your product fits now.
- SOM, the serviceable obtainable market, is the part of SAM you can win in a given period with the team and budget you have.
For an outbound team SAM is the number that matters day to day, since every list is drawn from it. TAM tells you how far the market goes once you add regions or segments.
How to calculate TAM
Top-down starts from a published market total, such as an analyst's figure for a whole industry, and cuts it down by share. It is quick and hard to check. Bottom-up counts the accounts that fit and multiplies by your price. It takes longer, and you can check every number in it.
A bottom-up count needs two inputs: how many companies fit, by industry and size, and what one account pays a year. In the US, the Census Bureau's Statistics of U.S. Businesses gives the number of firms and establishments, employment and payroll by industry and enterprise size, for the whole country and by state, metro area and county. It counts businesses with paid employees.1 Federal statistics code industries with NAICS, so the industry codes in your ideal customer profile carry straight over.2
What TAM tells an outbound team
In outbound, TAM caps how many accounts you can ever write to. Count it in accounts as well as dollars, then track how many of those accounts you have already reached. Once most of your SAM has heard from you, another sequence to the same pool mostly reaches people who already passed, and the next move is a new segment or a new region.
That count only holds if nobody is counted twice. In GetSales a person already in any table of your workspace is not added again, so each new list brings people your team does not already have.
Related
- B2B prospecting tool: AI Search turns a description of your buyers into a live search.
- Lead list builder: a list from one sentence, a link or a CSV, with nobody added twice.
- Data enrichment: work emails, fit scores and first lines for the people on your list.
Sources
- U.S. Census Bureau, Statistics of U.S. Businesses, latest data 2022, page last revised 11 March 2025. Read 28 October 2026.
- Office of Management and Budget, North American Industry Classification System: Revision for 2022, Federal Register, 21 December 2021. Read 28 October 2026.
Last updated: October 2026