What it means
When launching a product or setting sales targets, looking at the entire global market is unhelpful. Instead, you narrow your focus.
You start with the Total Addressable Market, which is everyone who could possibly buy your type of product. Then you narrow it to the Serviceable Available Market, which is the segment you can actually reach with your current distribution channels.
Finally, you calculate your Serviceable Obtainable Market, accounting for your budget, team size, and fierce competitors. This metric matters because investors and managers rely on it to build realistic financial forecasts.
If you claim you will capture fifty percent of a massive market on day one, experienced finance professionals will know your numbers are flawed. Your SOM keeps your feet on the ground and ensures your cash flow projections, hiring plans, and marketing budgets match reality.
In everyday business practice, you use your SOM to set achievable sales quotas and calculate realistic revenue targets for your business plan. It helps you figure out how many customers you need to acquire each month to break even.
By focusing on a specific, obtainable subset of buyers, you stop wasting money chasing impossible targets and concentrate your marketing spend where it will yield the highest return.
In practice
Real-world examples.
Example
A new coffee shop in Manchester calculates its SOM by looking at office workers within a ten minute walk who spend less than five pounds on morning coffee, yielding a realistic target of two thousand regular local customers.
Example
A regional accountancy firm targeting small manufacturing businesses in Yorkshire defines its SOM as forty local firms currently unhappy with their current provider and actively looking to switch accountants this financial year.
Example
A mobile app developer selling plant care subscriptions focuses their SOM on urban flat dwellers in London who own more than five indoor plants and pay for lifestyle apps, translating to fifteen thousand potential downloads.
Think of it
“Imagine a bakery opening in a large city. The entire city's population who eat bread is your total market. The people who live in your neighbourhood form your available market. The customers who will actually walk through your door on a rainy Tuesday, bypassing three rival bakeries, is your serviceable obtainable market.
Formula
Calculation
SOM = SAM x Market Share Percentage
For example, if your Serviceable Available Market (SAM) is ten thousand local businesses who need accounting software, and you realistically expect to capture five percent of them in your first year against two main competitors:
10,000 x 0.05 = 500 customers.
If each customer pays 120 pounds per year, your SOM revenue is 500 x 120 = 60,000 pounds.Case study
Seen in the real world.
GreenLeaf, a start-up selling eco-friendly cleaning products in Bristol, wanted to secure funding to expand operations. The founder initially claimed their market was every household in the United Kingdom, representing a value of two billion pounds. The investors quickly rejected this figure, pointing out that GreenLeaf had a tiny marketing budget and could not ship perishable liquids nationally without high costs.
The founder went back to the drawing board to calculate a realistic Serviceable Obtainable Market. They narrowed the focus to eco-conscious households within Bristol who shopped at independent zero-waste stores. Out of three hundred thousand Bristol households, roughly thirty thousand fit this profile. Factoring in two established local competitors and a modest delivery capacity, GreenLeaf estimated they could capture ten percent of this group in their first year.
This gave them a Serviceable Obtainable Market of three thousand households. At an average spend of fifty pounds per year, their realistic first-year revenue target was one hundred and fifty thousand pounds. Armed with this grounded figure, GreenLeaf secured the investment they needed because their financial model made logical, practical sense.
Watch out
Common mistakes.
- Assuming you can capture fifty percent or more of a market on day one.
- Confusing total market demand with your actual sales capacity and budget constraints.
- Failing to update your SOM as competitors enter the space or your resources grow.
Questions
People also ask.
How does SOM differ from TAM and SAM?
TAM is the total global market for a product. SAM is the portion you can reach geographically and operationally. SOM is the realistic slice you can actually win from competitors with your current resources.
How often should I recalculate my SOM?
You should review your SOM annually, or whenever you launch a new product, enter a new geographic region, or significantly increase your sales and marketing budget.
Why do investors care so much about SOM?
Investors use SOM to test whether your financial forecasts are grounded in reality. Inflated market sizes signal inexperienced leadership, whereas a well-calculated SOM shows strategic discipline.
From the founder's library
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