TAM, SAM and SOM
TAM is the whole market for the problem. The serviceable addressable market narrows it to what your product, model and geography can actually reach. The serviceable obtainable market narrows again to what you could realistically capture given competition and your own capacity. The three shrink dramatically at each step, which is why TAM alone is the least informative of them and the most often quoted.
Two ways to calculate it
Top-down starts from a published industry figure and applies percentages to carve out your slice. It is fast, it is easy to present, and it inherits every assumption in the source report. Bottom-up starts from the number of companies that fit your customer definition and multiplies by a realistic annual contract value. It is slower, more defensible, and usually produces a much smaller number.
The gap between the two methods is diagnostic. When a bottom-up count comes in at a fraction of the top-down figure, the top-down definition was almost certainly counting buyers who will never be reachable.
What it is actually for
TAM is a sizing check, not a plan. Its honest job is to answer one question: is this market large enough to be worth the effort, given how we intend to reach it? Once the answer is yes, the number stops being useful and the serviceable figures take over.
The operationally interesting version is usually the smallest one. Knowing there are a few thousand companies that fit your customer definition, and being able to name a meaningful proportion of them, is worth considerably more than a headline figure in the billions — because a list can be worked and a market size cannot.
Reading a TAM claim critically
TAM figures are produced for audiences — investors, boards, category-creation narratives — and the definition is the lever. Widening the category, adding an adjacent budget line or assuming a pricing model the company does not use can multiply the number without changing a thing about the business.
The questions that deflate a bad TAM are simple: what exactly is being counted, at what price, and are those buyers reachable through the channels this company actually operates? Applied to a competitor's public claims, the same questions tell you which market they intend to be judged on, which is a positioning statement dressed as arithmetic.
How IndustryLens handles this
A bottom-up market view starts with knowing who is actually in the category. Our intelligence hubs publish what we track per category — the companies, and what they have been doing — which is the observable input to that count.
Total Addressable Market: common questions
What is total addressable market?
Total addressable market is the entire revenue available for a product if it achieved complete adoption — the ceiling figure. Its honest job is a sizing check: is this market large enough to be worth the effort, given how we intend to reach it? Once the answer is yes, the number stops being useful.
What is the difference between TAM, SAM and SOM?
TAM is the whole market for the problem. The serviceable addressable market narrows it to what your product, model and geography can actually reach, and the serviceable obtainable market narrows again to what you could realistically capture given competition and your own capacity. The three shrink dramatically at each step, which is why TAM alone is the least informative and the most often quoted.
How do you read a competitor’s TAM claim critically?
Ask what exactly is being counted, at what price, and whether those buyers are reachable through the channels that company actually operates. TAM figures are produced for audiences and the definition is the lever — widening the category or assuming a pricing model the company does not use can multiply the number without changing the business. Applied to a rival, the answers tell you which market they intend to be judged on.