Market size
TAM, SAM and SOM built from the bottom up: Piko searches for the figures, shows the source next to each one, and multiplies them out. Then it does the same from the top down and makes the two methods argue — a bottom-up number that disagrees with a top-down one by an order of magnitude is the finding, not an error.
- Asks for
- What you sell, and to whom
- What you charge, or what you expect to charge
- Which market or geography you mean, if it is not everywhere
- Gives back
- TAM, SAM and SOM, with the arithmetic shown line by line
- Every input figure with the source it came from
- A top-down total built independently, and where the two disagree
- The assumptions the number rests on, listed so they can be challenged
- Plan
- Free
- Use next
- Business model canvas, Vision board, One-pager
What it gives you
Bottom-up Companies with 20–200 staff, UK + US 1,140,000 [source: ONS, SBA] Share with a product function 18% [source: survey, 2025] Product managers per company (median) 1.4 [source: report] Annual price $228 TAM = 1,140,000 × 0.18 × 1.4 × $228 ............ $65.5m Top-down cross-check ........................... $71m (8% apart — holds) Not found: churn by company size. SOM uses a stated 15% assumption instead.
How it works
Market sizing has a bad reputation because of how it is usually done: a number from an analyst press release, multiplied by one per cent, in a slide. Nobody can check it, so nobody believes it, and the people who should be arguing about whether the market exists argue about the slide instead.
This builds it the other way. How many of this kind of buyer are there, what would each pay, how often — each figure found by searching, with the page it came from printed next to it, so the chain from a public number to your total is visible all the way down. Where a figure cannot be found, it says so rather than substituting a plausible one.
Then it checks itself. The same market is sized top-down from a published total and worked downwards, and the two results are put side by side. When they are close you have a number worth defending; when they are not, the gap is the interesting part — usually it means one of the two definitions of the market is not the one you meant.
Who it is for
A PM or founder who needs a market size for a business case, an investor conversation or their own decision, and will be asked where the number came from.
Where it stops
Every figure it finds is a published figure, and published market data is often old, vendor-funded or defined differently from the market you mean. It shows you the source precisely so you can judge that. A sized market is also not demand: it is the ceiling if everyone who could buy did, which nobody ever does.
Questions people ask
What do TAM, SAM and SOM actually mean?
TAM is everybody who could ever buy this kind of thing, SAM is the part of that you could serve with what you sell today and where you sell it, and SOM is the part you could realistically win in a given period. Most arguments about market size are really arguments about which of the three somebody has quoted, which is why all three are shown here with the arithmetic rather than one headline number.
Where do the figures come from?
From searching the web during the run, with the page each figure came from printed next to it. That is the difference between a number you can defend and a number you cannot: somebody can open the source and disagree with it, which is the point. Where no usable public figure exists, it says the figure was not found and uses a stated assumption instead of quietly inventing one.
Why size it two ways?
Because a single method has no way of being wrong. Bottom-up multiplies counts and prices and tends to drift optimistic on the counts; top-down starts from a published total and tends to drift optimistic on the share. Running both and putting them side by side turns the exercise into a check: close together and you have something to defend, far apart and you have learned that your definition of the market is not what you thought.
Run it on your own work
Market size needs an account, because it writes against what you give it and remembers what you have told it before. It runs on the Free plan. Or see what the plans cost first.