[GTM glossary](/glossary.txt) Total addressable market

Market & Targeting

# Total addressable market (TAM)

Also known as: TAM

In short

Total addressable market (TAM) is the maximum annual revenue your product could generate if it reached every potential customer in a market. It is a ceiling, not a forecast.

Teams use TAM to judge whether a market is big enough, to prioritize segments, and to set coverage and hiring plans. Investors use it to judge upside.

## How to calculate TAM

There are two standard approaches. Use both and compare them.

### Bottom-up market sizing

Count the real number of target accounts and multiply by your expected annual contract value. For example, 12,000 companies that match your ICP × $15,000 per year = $180 million TAM.

This is the most credible method for B2B because the account count comes from real company data.

### Top-down market sizing

Start with an industry report for the total market and narrow it by segment, region, or product category. It is fast but depends on third-party estimates that are often broad.

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## Why bottom-up beats top-down in B2B

A bottom-up TAM is built from a list of actual accounts. That list can then be segmented, scored, and handed to sales, so the sizing exercise turns directly into a target account list.

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## Using TAM in go-to-market planning

* **Segment prioritization:** Rank segments by size and fit to choose where to go first.
* **Territory design:** Split the account universe fairly across reps.
* **Capacity planning:** Check whether your headcount can cover the market you are targeting.
* **Whitespace analysis:** Compare TAM against current customers to find untouched accounts.

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## Total addressable market FAQs

**What is total addressable market (TAM)?**

Total addressable market is the total revenue opportunity available if every potential customer for your product bought it. It is the upper limit of your market and is used for planning and investor discussions.

**How do you calculate TAM?**

The bottom-up method multiplies the number of target accounts by your average annual contract value. The top-down method takes an industry-wide market figure and narrows it by segment and geography. Comparing both makes the estimate more reliable.

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

TAM is the entire market opportunity. SAM is the part of it your product and go-to-market can serve. SOM is the portion you can realistically win in the near term, given your resources and competition.

Share term

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## More related phrases

* [Serviceable obtainable market](/glossary/serviceable-obtainable-market.txt)
* [TAM mapping](/glossary/tam-mapping.txt)
* [Bottom-up market sizing](/glossary/bottom-up-market-sizing.txt)

## Similar phrases

* [TAM, SAM, and SOM](/glossary/tam-sam-som.txt)  
TAM, SAM, and SOM are three nested market-size estimates: the total market, the part you can serve, and the part you can realistically win.
* [Ideal customer profile (ICP)](/glossary/ideal-customer-profile.txt)  
An ideal customer profile (ICP) describes the type of company that gets the most value from your product and brings you the most revenue.
* [Account tiering](/glossary/account-tiering.txt)  
Account tiering groups target accounts into tiers by fit and potential value, so the highest-value accounts get the most personalized effort.
* [Market sizing](/glossary/market-sizing.txt)  
Market sizing is the process of estimating how many potential customers exist for your product and how much revenue they represent, so you can choose where to focus.
* [Serviceable addressable market (SAM)](/glossary/serviceable-addressable-market.txt)  
Serviceable addressable market (SAM) is the part of the total addressable market your product, pricing, and go-to-market model can realistically serve, typically a subset of TAM.