TAM SAM SOM examples — 6 worked cases
Six worked TAM/SAM/SOM calculations across different startup categories. Real numbers, real reasoning, and the pattern each one demonstrates.
What does a worked TAM SAM SOM calculation look like?
Six of them, with realistic numbers and the reasoning shown. The useful part is where top-down and bottom-up disagree, because that gap is where the hidden assumption is sitting.
- Composites: the companies are fictional, but the maths, the ranges and the reasoning are what turns up in real sessions
- Top-down inflates because industry reports include adjacent revenue you cannot reach. Bottom-up underestimates because it misses expansion
- Realistic five-year capture: 1 to 3% in a competitive market, 5 to 15% in a vertical with weak incumbents
- Anything above 15% in five years needs an explanation rather than an assumption
- If the two methods disagree by more than about five times, one of them is carrying an assumption that is wrong
Example 1
B2B SaaS — accounting tool for SMBs
Realistic and venture-friendly. SOM gives a clear funnel target. Strong B2B SaaS profile.
Pattern:Standard B2B SaaS — narrow ICP, defensible 1% share.
Example 2
Consumer app — fitness subscription
Consumer is hard. Low ARPU + high churn = small SOM despite huge TAM. Marginal venture case unless network effects unlock 5x bigger SOM.
Pattern:Consumer subscription — TAM looks great, SOM tells the truth.
Example 3
Vertical SaaS — practice management for dentists
Smallest TAM, largest SOM. Narrow markets often beat broad ones — narrow = defensible.
Pattern:Vertical SaaS — small TAM, deep ARPU, high realistic capture.
Example 4
Two-sided marketplace — freelance designer platform
Marketplace TAM is GMV (gross merchandise value). SOM here is take rate × GMV captured. Investors look at GMV growth + take rate separately.
Pattern:Marketplace — model TAM as GMV, SOM as take rate. Different math than SaaS.
Example 5
Hardware — IoT plant monitor
Hardware unit economics are brutal — $40 BOM + 35% retail margin = $14/unit profit. Need 140K units for $2M revenue.
Pattern:Hardware — small TAM relative to effort, slim margins. Usually NO-GO unless capital is plentiful.
Example 6
Enterprise SaaS — security ops for Fortune 5000
Enterprise sales = long cycle, big ACV. SOM small in customer count (300 customers) but big in revenue. Different funnel than SMB SaaS.
Pattern:Enterprise — count customers in hundreds, ACV in 6 figures, SOM in tens of millions.
Calculate your own TAM/SAM/SOM
Try our free interactive calculator with these example presets — or input your own numbers. Pick a vertical preset and see how SOM math actually works for your category.