Founders love big numbers. You see it in every pitch deck. A slide shows a giant market potential, often in the billions. The logic seems simple: if we capture just a tiny fraction, we will be successful. This thinking is a trap.
It distracts from the real work. Your actual market is much smaller and far harder to win. Experienced operators and investors know this. Big numbers often signal a lack of focus.
TL;DR. Stop chasing huge TAM figures. Calculating your true market potential requires a bottom-up approach, not a top-down guess. Define your Ideal Customer Profile, count those companies, and multiply by your price. This gives you a realistic target (your SOM). A smaller, addressable market is more valuable than a hypothetical billion-dollar one.
What are TAM, SAM, and SOM?
These acronyms define your market at different levels. TAM is the total global demand. SAM is the part you can serve with your product. SOM is the realistic piece you can capture in the near term. You should focus almost exclusively on your SOM.
Here is a simple breakdown:
- Total Addressable Market (TAM): The total revenue opportunity for a product or service. This is a theoretical ceiling and mostly irrelevant for an early-stage company.
- Serviceable Addressable Market (SAM): The segment of the TAM that fits your business model and go-to-market strategy. It is narrowed by geography, industry, or other constraints.
- Serviceable Obtainable Market (SOM): Your real target. It is the portion of the SAM you can realistically win with your current team, product, and resources.
The Top-Down Calculation Trap
Many founders make the same mistake. They take a number from a market report and claim 1% of it. “The global market is $50 billion, so our target is $500 million.”
This method is lazy. It ignores competition, switching costs, and the actual needs of specific customers. It signals to investors that you have not done your homework. A huge TAM is a vanity metric, not a business plan.
The Better Way: Bottom-Up Calculation
A bottom-up analysis is far more credible. It forces you to be specific. The formula is simple: the number of target customers multiplied by your average annual price.
Start by defining your Ideal Customer Profile (ICP). Be precise. How many employees? What industry? Which country? Use company databases or LinkedIn to count them. This gives you a concrete number of potential accounts.
Then, multiply that number by your planned annual contract value (ACV). The result is your initial SOM. It is a tangible, defensible number that you can build a sales and marketing plan around.
Forget the billions. The vast, theoretical market potential does not pay salaries. A well-defined, reachable market of a few hundred customers does. Winning this smaller segment gives you traction, revenue, and proof. Real growth starts with a narrow focus, not a big number on a slide.
