How to use it
- Choose a starting point: Bulgaria, the Netherlands or your own count of potential customers.
- Adjust the share of that population that could buy, for example online shoppers or households in your target region.
- Enter the number of purchases per customer per year and the average value per purchase.
- Set the share of the market you can serve (SAM) and the market share you consider realistic (SOM).
- Read the three values, then repeat with cautious and optimistic inputs to see the range.
Formula and logic
The calculator multiplies three layers:
- TAM = number of potential customers × purchases per year × average value per purchase
- SAM = TAM × share of the market you serve
- SOM = SAM × realistic market share
The default population figures are 6,433,302 for Bulgaria and 18,087,633 for the Netherlands (World Bank, 2025). The default share of online buyers is 51.2% for Bulgaria and 94.2% for the Netherlands, the proportion of people aged 16–74 who bought something online in the previous 12 months (Eurostat, isoc_ec_ib20, 2025). Multiplying the two gives about 3.29 million potential online buyers in Bulgaria and about 17.04 million in the Netherlands.
The Eurostat share describes people aged 16–74, but the default applies it to the whole population, including children and people over 74, so it overstates the base. Narrow it to your real target group before drawing conclusions.
How to read the result
TAM is a ceiling, not a forecast: it assumes every potential customer buys from someone. SAM reflects the limits of your offer, such as the regions you deliver to, the channels you sell through and the segments your product suits. SOM is the figure a business plan should rest on, and it should be compared with the size of existing competitors; if your SOM implies a larger share than the current market leader holds, revisit the assumption.
The calculator gives a top-down estimate. Check it against a bottom-up view built from your own capacity, the number of sales contacts per month and expected conversion. When the two approaches give very different answers, the gap usually points to the assumption that needs research, most often purchase frequency or the share of buyers who would switch. Our article on TAM, SAM and SOM with a worked example shows both methods, and a market sizing study replaces the assumptions with measured data. For the latest consumer figures, see the consumer data section.
Frequently asked questions
How do TAM, SAM and SOM differ?
Think of three nested circles. TAM covers all demand for the category in a market, SAM the part of it your business model can reach, and SOM the slice of SAM you can realistically win in the next few years. A delivery service in one city, for example, has a national TAM, a SAM limited to that city and a SOM limited by its capacity and competitors.
Should I use a top-down or a bottom-up approach?
Use both. Top-down estimates, like this calculator's, start from population or industry statistics and are quick, but they depend heavily on a few percentages. Bottom-up estimates start from your own sales capacity, prices and conversion rates and are harder to inflate. Presenting both, and explaining the gap between them, makes a business plan far more convincing.
Where do I find purchase frequency and average value?
From your own sales data if you already trade, from industry associations and company filings in desk research, or from a survey of category buyers. Official statistics rarely give values for a specific product. Where no reliable figure exists, a short survey asking about the last purchase is usually the most direct way to fill the gap.
Can I use the calculator for a B2B market?
Yes. Replace the population with the number of businesses in your target sector and size band, taken from a business register or Eurostat business statistics, and use the number of orders and the average order value per business. B2B markets are often concentrated, so check whether a few large buyers account for most of the demand.
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