Free TAM Calculator for SaaS Startups
Estimate your market size in seconds with AI — no spreadsheets required
TAM (Total Addressable Market)
The total revenue opportunity available if you achieved 100% market share. Think "everyone who could possibly use this."
SAM (Serviceable Addressable Market)
The portion of TAM your business can realistically serve based on your location, capabilities, and business model.
SOM (Serviceable Obtainable Market)
The portion of SAM you can realistically capture in the near term, considering competition and resources.
This is just the TAM. Get the full market research package:
- Competitor analysis
- SWOT analysis
- GTM strategy
What is TAM SAM SOM and why it matters for SaaS founders
Before you write a single line of code, you need to know if your market is big enough to build a business on. TAM, SAM, and SOM are the three numbers every investor, accelerator, and serious founder uses to answer that question.
TAM — Total Addressable Market
TAM is the total revenue opportunity if you captured 100% of your market. It answers: "How big is this problem in the world?" For a project management SaaS targeting US tech companies, TAM might be $4B/year. You won't capture all of it, but it sets the ceiling.
SAM — Serviceable Addressable Market
SAM is the slice of TAM you can realistically reach with your current product, pricing, and distribution. If your tool only works in English and targets SMBs, your SAM is much smaller than your TAM. This is the number that tells investors whether your business model makes sense.
SOM — Serviceable Obtainable Market
SOM is what you can actually capture in the next 12-24 months, given your team size, budget, and competition. A realistic SOM for an early-stage SaaS is typically 1-5% of SAM. If your SOM is large enough to build a sustainable business, you have a viable idea.
How to use this TAM calculator
Enter four inputs: your sector, target segment, geography, and estimated number of addressable customers plus your monthly price. The calculator uses AI to refine the estimates and returns TAM, SAM, and SOM with the reasoning behind each number.
For best results, be specific. "B2B SaaS for dental clinics in Spain, 50-200 employees" gives better results than "healthcare software globally".
TAM SAM SOM example: a project management SaaS
Say you're building a project management tool for freelance designers in the US. There are approximately 2.3 million freelance designers in the US. At $29/month, your TAM is around $800M/year. Your SAM, targeting designers who already use paid tools, might be $120M. Your SOM for year one, aiming for 0.5% market share, is $600K ARR — a very achievable first target.
When to calculate TAM SAM SOM
Calculate it before you build, not after. The goal is to validate that the market is large enough to justify the investment. If your SOM is under $100K ARR at realistic pricing, the market may be too small for a SaaS business. If it's over $1M, you have a real opportunity worth pursuing.
Frequently asked questions
Most VCs look for a TAM of at least $1B to consider a SaaS investment. For bootstrapped founders, a TAM of $50M-$500M is often ideal — large enough to build a real business, small enough that big players haven't dominated it yet.
This calculator gives you a directional estimate based on your inputs and AI-assisted market sizing. It's designed for early validation, not for investor decks. For a more detailed report including competitor revenue estimates and market growth rates, use ReadyToRelease.
They're often used interchangeably. TAM is the maximum theoretical revenue if you had 100% market share. Market size usually refers to the current total spending in a category, which is a bottom-up measure. Both are useful; TAM is more common in startup pitches.
Use the top-down method: find the total number of potential customers (from industry reports, LinkedIn, government data) and multiply by your annual price per customer. This calculator automates that process using AI to estimate the inputs you don't have.