The total theoretical demand available if a business could serve the entire relevant market.
Total Addressable Market (TAM) quantifies the overall revenue opportunity available to a product or service if 100% market share were theoretically achieved within its target market.
The maximum amount of money you could make every year if literally every single potential customer in the world bought your product.
Selling specialized cloud ERP software to private hospitals in India. If there are 15,000 qualified hospitals and each would pay ₹10 lakh annually, your TAM is ₹1,500 crore.
Bottom-up TAM: 20,000 potential enterprise clients in India × ₹5,00,000 average annual subscription = ₹1,000 crore TAM. Serviceable Addressable Market (SAM) = ₹350 crore. Serviceable Obtainable Market (SOM) = ₹70 crore.
Investors immediately discount generic "top-down" TAM calculations derived from quoting global research reports. High-credibility TAM calculations are always built bottom-up from verifiable unit pricing and customer counts.
TAM defines your growth ceiling. If your addressable market is small (e.g. ₹50 crore), the business should be run as a lean, cash-generative boutique rather than attempting to raise institutional venture capital.