Summary of Market Sizing in Business Planning

## Introduction Market sizing is the process of estimating how large the potential demand is for a product or service. It quantifies opportunity in terms investors, founders, and managers can use to make decisions: revenue potential, units sold, users engaged, or other relevant metrics. Good market sizing helps you decide whether a venture is worth pursuing and how to prioritize resources. > **Definition:** Market sizing is the process of estimating the potential demand for a product or service within a specific market segment or industry, usually expressed in revenue, units, or users. ## Why market sizing matters - Helps set realistic sales and revenue targets - Guides product prioritization and geographic expansion - Supports financial forecasting and investor pitches - Informs pricing, marketing channels, and operations - Exposes underserved niches and competitive gaps Did you know that investors often ask for TAM, SAM, and SOM before considering funding to understand upside potential and realistic near-term traction? ## Core concepts: TAM, SAM, SOM ### Total Addressable Market (TAM) > **Definition:** The total demand for a product or service across all potential customers and segments, without constraints of geography, distribution, or company capability. Example: The TAM for solar panels in India includes residential, commercial, industrial, and government adopters across the whole country. ### Serviceable Addressable Market (SAM) > **Definition:** The portion of TAM that your company can target given product features, geographic reach, regulatory constraints, and go-to-market strategy. Example: A solar company that targets states with strong incentives (Gujarat, Rajasthan, Karnataka) would define SAM as the demand within those states. ### Serviceable Obtainable Market (SOM) > **Definition:** The share of SAM that the company can realistically capture within a defined time frame, considering competition, capacity, and distribution. Example: With current production, distribution, and sales channels, a company might estimate capturing 2% of SAM over three years; that is the SOM. ## Comparing TAM, SAM, SOM | Metric | Scope | Use case | Typical expression | |---|---:|---|---:| | TAM | Entire potential market | Long-term vision, investor pitch | Revenue/year or users/year | | SAM | Targetable portion of TAM | Operational planning, go-to-market | Revenue/year in target regions/segments | | SOM | Realistic near-term capture | Forecasts, capacity planning | Revenue/year or market share % | ## Approaches to estimate market size 1. Top-down approach - Use published industry reports, government statistics, and market research to estimate TAM. - Advantages: fast, uses authoritative sources. - Limitations: may be broad, not startup-specific. 2. Bottom-up approach - Build estimates from unit economics, pricing, addressable customers, and planned distribution. - Advantages: more realistic for your model; ties to operations and capacity. - Limitations: time-consuming and sensitive to assumptions. 3. Value-theory / demand-based approach - Estimate willingness to pay and frequency of purchase to infer revenue potential. - Useful when price and behavior data are available. ### Practical steps (recommended order) 1. Revisit your problem and customer segments (from prior customer validation). 2. Choose a primary metric: revenue, units, or users. Example: revenue/year. 3. Estimate TAM using a credible source (top-down) or aggregate all potential buyers (bottom-up). 4. Define SAM by applying realistic geographic, regulatory, or segment constraints. 5. Compute SOM by applying market-share assumptions, distribution reach, and capacity over a defined timeframe. 6. Sensitivity-test optimistic, base, and conservative scenarios. ## Bottom-up example (concise) Assume you sell a subscription app targeting urban professionals in three cities. Steps: - Addressable customers per city: $N_1$, $N_2$, $N_3$. - Penetration