What’s the best way to estimate tam and sam for a niche b2b software product?

[EricJ]

I’m trying to map out the entire addressable market for a niche B2B software product, but I keep hitting a wall when it comes to defining the realistic serviceable available market. My initial TAM figure feels huge and almost meaningless, and I’m not sure my method for narrowing it down to SAM is sound.

[Victoria.G]

I started with a tight ICP and picked 3 verticals where the problem actually exists. Then I pulled rough counts from public sources and asked who would realistically have the budget to sign within a year. It made the market feel less abstract and the next steps clearer.

[KennethJ]

The bottom up route felt more honest: estimate the annual value per customer, multiply by how many target accounts you could reach with your current sales motion, then dial in funnel drop. It takes longer, but the numbers land on something usable.

[Robert_C]

One trap was counting all companies in a sector and assuming we could reach them all. We used a realistic penetration rate and a time frame (first 12–24 months) to bring the figure down to something actionable.

[AlexanderT]

Geography and who buys matters. If you only have a local salesperson or a partner network in one region, that slice becomes your practical market overnight.

[KevinH]

Question: would you run a short pilot with a handful of customers to validate how big the served market actually is before you commit to a number?

[Jack_R]

I kept drifting into thoughts about product-market fit and support strain, and realized size helps only if the pain is real and the org buys in. We adjusted the roadmap to win a few big logos first instead of chasing a broad market.