---
title: "What Is Total Addressable Market (TAM)? Definition | ONEGTMLAB"
description: "Total addressable market (TAM) is the full revenue opportunity for a product. Learn how to size TAM bottom up and how it relates to SAM and SOM."
canonical: https://www.onegtmlab.dev/glossary/total-addressable-market
---

# What Is Total Addressable Market (TAM)? Definition | ONEGTMLAB

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GTM Glossary

# Total Addressable Market (TAM)

Total addressable market (TAM) is the total revenue opportunity available if a product won every possible customer in its market, often expressed as a dollar value or a count of target accounts.

Also called: TAM, total available market

## Why it matters

TAM sets the ceiling for a go-to-market plan. A top-down TAM starts from broad industry estimates, while a bottom-up TAM counts the actual companies that match the ideal customer profile and multiplies them by an expected contract value. Outbound teams often work from the bottom-up version because it produces a real account list that can be enriched, segmented and assigned to reps.

TAM is often paired with two narrower figures. Serviceable addressable market (SAM) is the part a company can reach with its current product, geography and channels. Serviceable obtainable market (SOM) is the share it can realistically win in the near term. Treating TAM as if it were SAM inflates targets and spreads outreach across accounts the company cannot serve.

## Example

A company sells scheduling software to dental clinic groups in the US. Using a company database filter, it finds 4,000 clinic groups that match its profile. At an average contract of $6,000 a year, its bottom-up TAM is $24 million in annual revenue. The team then splits those 4,000 accounts by region and assigns each region to a rep.

## Related terms

-   [Ideal Customer Profile (ICP)](/glossary/ideal-customer-profile)
-   [Firmographics](/glossary/firmographics)
-   [Go-to-Market (GTM)](/glossary/go-to-market)
-   [Account-Based Marketing (ABM)](/glossary/account-based-marketing)
-   [Annual Recurring Revenue (ARR)](/glossary/annual-recurring-revenue)

## Related service

[Account-Based Marketing Tier your named accounts, act on their signals and reach the whole buying committee.](/services/account-based-marketing)

## Related playbooks

-   [Data Enrichment Playbook Reuse what you hold, enrich the company first, judge from the description, and keep every raw payload.](/growth-playbooks/data-enrichment)
-   [Outbound Sales Playbook From a signal or event list to the right buyers, one channel each, with every row explained.](/growth-playbooks/outbound-sales)

## Questions people ask

### What is the difference between TAM, SAM, and SOM?

TAM is the whole market if you won every possible customer. SAM, the serviceable addressable market, is the part your product and channels can actually serve. SOM, the serviceable obtainable market, is the share of SAM you can realistically win in a given period.

### How do I calculate my TAM?

Bottom-up is usually the most useful for B2B: count the companies that match your ideal customer profile, then multiply by the average annual contract value you expect from each. Top-down estimates start from industry market-size figures and narrow them, but are harder to act on.

[← All GTM terms, A to Z](/glossary)

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