What is total addressable market (TAM)?
Total addressable market is the full annual revenue available in your category. Here is how TAM, SAM and SOM fit together, the formulas, a worked AED example, the common mistakes and how to include market growth.
Total addressable market (TAM) is the total annual revenue available if every potential customer for your product category bought from you. It is usually sized with two narrower figures: serviceable addressable market (SAM), the part your product, channels and geography can serve, and serviceable obtainable market (SOM), the share you can realistically win.
How do you calculate TAM, SAM and SOM?
The bottom-up method multiplies customer counts by what each customer pays per year, then narrows the pool step by step.
| Measure | Question it answers | Formula |
|---|---|---|
| TAM | How big is the whole category? | All potential customers × annual revenue per customer |
| SAM | How much can we serve today? | Customers within our product, channel and geographic reach × annual revenue per customer |
| SOM | How much can we win? | SAM × realistic market share |
The top-down method starts from a published market size and applies percentages. It is quicker, but it often overstates what a specific company can reach.
TAM, SAM and SOM example
An illustrative bookkeeping software company sells to small businesses in the GCC for AED 3,000 a year:
- TAM: 200,000 eligible businesses × AED 3,000 = AED 600 million.
- SAM: 60,000 of them are in the UAE and Saudi Arabia, the markets it sells to today = AED 180 million.
- SOM: a 3% share of SAM within three years = 1,800 customers, or AED 5.4 million a year.
Common mistakes
- Quoting TAM as the goal: investors and leadership plan on SOM, not TAM.
- Mixing units: keep every figure as annual revenue, not one-time sales or customer counts.
- Freezing it: markets grow, so apply a growth rate (CAGR) and revisit the numbers each year.
Related terms
Once you know your SOM, define who sits inside it with a buyer persona, and check rivals with the competitor analysis template.
How Grower helps
Grower's AI marketing planner sizes TAM, SAM and SOM with CAGR and a five-year forecast that recalculate as inputs change, alongside the market and competitive landscape and your brand and positioning strategy.
Frequently asked questions
What is the difference between TAM, SAM and SOM?
TAM is the whole category's annual revenue if everyone who could buy did. SAM is the part your product, channels and geography can actually serve today. SOM is the share of SAM you can realistically win in the next few years, given competitors and budget. Each figure is a subset of the one before it.
Should I use top-down or bottom-up market sizing?
Use bottom-up whenever you can. Counting real potential customers and multiplying by realistic annual revenue gives a figure you can defend and turn into targets. Top-down figures from industry reports are useful as a sanity check, but they often include segments, regions or price points you will never reach, which inflates TAM.
How do I include market growth in TAM?
Apply a compound annual growth rate. TAM in year n equals today's TAM multiplied by (1 + CAGR) to the power of n. At an illustrative 10% CAGR, an AED 600 million TAM becomes about AED 966 million in five years. Grow SAM the same way, then set SOM targets for each year.
Size your own market in minutes with the free TAM SAM SOM calculator, or book a Grower demo to see the AI marketing planner.