How do I calculate total addressable market?

How do I calculate total addressable market is mainly about estimating the maximum annual revenue available under a clearly defined market scope. A reliable approach is to use top-down category data, bottom-up customer counts and spending, or a value-based method tied to economic benefit. For example, for a business service, multiply eligible companies by annual spending and test the result against category totals and competitor scale. The main caution is that including customers who cannot use the product or applying unrealistic prices produces an inflated TAM. The final output should provide a market range supported by formulas, sources, definitions, and sensitivity to the most uncertain assumptions.