TAM SAM SOM calculator — free interactive tool
Pick an industry preset, adjust the inputs, see TAM/SAM/SOM live. No signup, no data sent anywhere — runs entirely in your browser.
How do you calculate TAM, SAM and SOM?
Population, times your ICP share, times the reachable share, times the capture rate, times ARPU. The arithmetic is trivial; all of the accuracy lives in those five inputs, which is why they are shown rather than hidden.
- The chain: population, ICP share, reachable share, capture rate, ARPU
- Directionally accurate, not investor-ready. The maths is correct; the accuracy is whatever your inputs are
- It runs entirely in your browser. Nothing is tracked, nothing is stored, nothing reaches a server, and a refresh clears it
- Inputs are not encoded in the URL, so there is no share link. Screenshot the inputs together with the outputs if someone else needs to see it
- Use it for a back-of-envelope figure you can defend, not for a number to drop into a deck unchecked
Try a preset
Inputs
Everyone who could conceivably exist in this market.
= 33.00M people
What fraction actually matches your ideal customer profile?
Of those, how many can you realistically reach via your channels & geography?
What share will you realistically capture in 3–5 years? Be honest.
Annual revenue per paying customer.
Outputs
Total addressable · 2.64M people
Serviceable · 924.0K people
Realistic capture · 9.2K customers
Sanity check: if your SOM is <$10M, the business may not be venture-scale. If your SOM is >$1B, your assumptions are probably too optimistic — go back and tighten ICP or market share.
Inputs run locally. We don't store anything.
How to use it
1. Start with a preset. Three industry presets (B2B SaaS, Consumer mobile, Vertical SaaS for dentists) load realistic baseline numbers. Even if your idea doesn't match exactly, the closest preset gives you a sane starting point.
2. Adjust inputs to your idea. Population (total addressable population), ICP fit % (what fraction matches your ideal customer), reachable % (geography + channels), market share % (5-year realistic), ARPU (annual revenue per user).
3. Read the output. Three values updated live: TAM (the ceiling), SAM (what you can serve), SOM (what you'll realistically capture). Visual bars show relative size — if your SOM bar is invisible compared to TAM, your capture rate or ICP filter is too narrow.
4. Sanity check. Calculator shows guidance: SOM under $10M is borderline-not-venture-scale; SOM over $1B usually means inputs are too optimistic. Adjust accordingly.
When this calculator helps (and when it doesn't)
✓ Good for
- • Back-of-envelope sanity check before deeper research
- • Comparing 2–3 idea variations side by side
- • Stress-testing "if we only capture X%" assumptions
- • Internal team alignment on rough scale
✗ Not good enough for
- • Investor pitch decks (need cited sources)
- • Bank loans or government grants (need detailed projections)
- • Final go/no-go on $1M+ commitments
- • Any number that will be public or contractually binding
Need cited TAM/SAM/SOM?
The calculator above is for back-of-envelope. For pitch-deck quality with cited sources, our 30-min validation session pulls live market data, finds comparable companies, and produces TAM/SAM/SOM with sources for every number.
Get cited market sizing free →15 min · up to 20 reports · Real sources