Total Addressable Market (TAM)
The total revenue opportunity available if a product achieved 100% market share, representing the maximum potential size of the market and used to evaluate business opportunity and set growth targets.
TAM defines the ceiling of your opportunity. It is typically estimated top-down (total industry revenue applicable to your product), bottom-up (number of potential customers times average revenue per customer), or through value theory (total value your product creates for the market). A credible TAM analysis uses multiple approaches and reconciles the estimates.
TAM matters for strategic decisions: market entry, pricing, positioning, and fundraising. A $100M TAM business should be built differently than a $10B TAM business. The former might be a profitable niche play; the latter justifies aggressive venture-backed expansion. Investors use TAM to assess whether a company can achieve the scale needed to justify their investment.
For growth teams, the practical metric is SAM (Serviceable Addressable Market): the portion of TAM you can realistically reach with your current product, pricing, and go-to-market approach. SAM is always smaller than TAM. An AI writing tool's TAM might include all content creation ($50B+), but its SAM might be marketing teams at B2B SaaS companies ($2B). Growth strategy should focus on capturing SAM efficiently while expanding it over time through new features, segments, and use cases.
Related Terms
Growth Loop
A self-reinforcing cycle where each cohort of users generates inputs (data, content, referrals) that attract the next cohort, creating compounding growth.
Churn
The rate at which customers stop using or paying for a product over a given period, typically measured as monthly or annual churn percentage.
Activation Rate
The percentage of new signups who complete a key action (the 'aha moment') that correlates with long-term retention and product value realization.
Product-Led Growth (PLG)
A go-to-market strategy where the product itself drives acquisition, activation, and expansion through self-serve experiences rather than sales-led motions.
Viral Coefficient (K-Factor)
The average number of new users each existing user brings to the product, where a K-factor above 1.0 indicates self-sustaining viral growth.
Net Revenue Retention (NRR)
The percentage of recurring revenue retained from existing customers over a period, including expansion, contraction, and churn — where 100%+ indicates growth without new customers.