Market Sizing & TAM SAM SOM Calculator
Business Planning & Strategy
Quick Answer
Describe your market, target customer, and pricing. Paste into Claude or ChatGPT. Receive a rigorous TAM SAM SOM calculation with transparent assumptions and investor-ready presentation.
What You Get
A complete TAM SAM SOM analysis using both top-down and bottom-up methodology, transparent assumptions for each number, a sanity check on the sizing, and investor-ready language to present the market opportunity.
Who Is This For
Founders preparing investor pitches, entrepreneurs writing business plans, and product managers evaluating market opportunities.
About This Template
Market sizing is a required element of every investor pitch and business plan, yet most founders either guess the numbers or cite third-party research without understanding the methodology. This template guides you through both top-down and bottom-up market sizing approaches, then uses AI to produce a rigorous TAM SAM SOM analysis with transparent assumptions, methodology explanation, and investor-ready presentation of the numbers.
Fill In Your Details
What you sell and who you sell it to
Detailed description of your ideal customer including size, industry, geography
Annual contract value or average transaction value e.g. $1200 per year per customer
e.g. United States only, North America, Global
Any third-party market size data you have found — even rough numbers help calibrate the analysis
Your best estimate of how many businesses or people fit your ICP
e.g. 1 percent of the market in 5 years, 500 customers by year 3
Gather these details then use them to fill in the prompt below.
AI Prompts
Generate TAM SAM SOM analysis
Paste this prompt into Claude or ChatGPT with your inputs filled in.
You are a market research analyst helping a startup calculate their TAM SAM SOM for an investor presentation. Using the information below, produce a rigorous market sizing analysis. Business: [business_description] Target customer: [target_customer] Price point: [price_point] Geography: [geography] Known market data: [known_market_data] Estimated potential customers: [estimated_customers] Realistic 5-year target: [realistic_market_share] Produce: 1. TAM (Total Addressable Market) — use top-down methodology from any available market data 2. SAM (Serviceable Addressable Market) — narrow to the segment you can realistically serve given geography, price point, and product scope 3. SOM (Serviceable Obtainable Market) — your realistic capture in 3-5 years based on stated targets 4. Bottom-Up Validation — calculate SAM from the number of potential customers multiplied by price point to cross-check the top-down number 5. Assumptions — list every assumption behind each number explicitly 6. Sanity Check — does the SOM represent a plausible market share percentage of SAM? 7. Investor Presentation Language — how to present this market opportunity in 2-3 sentences for a pitch deck Be rigorous and transparent. Investors can spot inflated market sizing immediately.
Sample Output
This is an example of what AI produces when you use this template.
TAM SAM SOM Summary
TAM: $47B — total global spend on financial close and reconciliation software and services for businesses with 10 or more employees. SAM: $8.2B — US-based SaaS and professional services companies with 10-500 employees that use cloud accounting software. Bottom-up validation: approximately 680,000 US companies fit the ICP profile at an average $12,000 annual contract value, implying an $8.2B SAM consistent with the top-down figure. SOM: $41M — targeting 3,400 customers representing 0.5 percent of SAM by year 5, consistent with achieving $41M ARR.
Investor Presentation Language
The US market for AI-powered financial close automation is $8.2B and growing at 18 percent annually as cloud-native SaaS companies replace legacy reconciliation processes. At a 0.5 percent market share target by year 5, our serviceable obtainable market represents $41M in ARR — a realistic and defensible target given our current traction and go-to-market strategy.