market-sizer

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Use this skill when users need to calculate market size (TAM/SAM/SOM), assess market opportunity, validate market potential, or determine if a market is big enough to pursue. Activates for "how big is the market," "TAM," "market sizing," or market opportunity questions.

2installs

Sourceshipshitdev/library

Added on2026-02-04

NPX Install

npx skill4agent add shipshitdev/library market-sizer

SKILL.md Content

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Market Sizer - TAM/SAM/SOM Calculator

Overview

Market sizing specialist applying Hexa's practical market assessment methodology. Help founders determine if their target market is big enough using rigorous bottom-up AND top-down analysis.

Hexa's Core Principle: "Make sure you can approximate how big the market is—ideally by confronting bottom-up and top-down analysis."

When This Activates

"how big is the market"
TAM, SAM, or SOM questions
"is the market big enough"
Validating market opportunity
Investor conversations about market
"size this opportunity"

Core Definitions

Term	Definition	What It Means
TAM	Total Addressable Market	Everyone who could theoretically buy
SAM	Serviceable Available Market	The segment you can actually reach
SOM	Serviceable Obtainable Market	What you can realistically capture in 3-5 years

The Framework: Dual-Analysis

Market Size = Bottom-Up Analysis + Top-Down Analysis + Timing Assessment

Bottom-Up (Build from Units)

TAM = Total Potential Customers × Annual Revenue Per Customer
SAM = TAM × Percentage You Can Reach
SOM = SAM × Realistic Market Share (1-5% years 1-3)

Top-Down (Start from Industry)

Start with industry reports, narrow to your slice.

Common Sources: Gartner, Forrester, Statista, IBISWorld, CB Insights

Market Size Adequacy Test

Your Goal	Required SOM	Required SAM
Lifestyle ($500K-2M/year)	$500K-2M	$10M+
Venture-scale ($10M+ ARR)	$10M+	$100M+
Unicorn potential ($100M+)	$100M+	$1B+

The 10% Rule: If you captured 10% of SAM, would that be interesting?

Sanity Check

The two methods should be within 2-3x of each other.

Variance	Meaning	Action
< 50%	Good alignment	Proceed with confidence
50-200%	Reasonable	Investigate discrepancy
> 200%	Major misalignment	One method is wrong

Market Stage Assessment

Stage	Characteristics	Implication
Emerging	< $100M, few players	High risk, high reward
Growing	20%+ growth, new entrants	Good timing
Mature	< 10% growth, clear leaders	Need strong wedge
Declining	Negative growth	Avoid unless transforming

Integration

Skill	When to Use
`idea-validator`	Validate the idea for this market
`startup-icp-definer`	Define ideal customer in this market
`competitive-intelligence-analyst`	Deep dive on competitors
`fundraise-advisor`	Present market size to investors

For complete bottom-up/top-down worksheets, market dynamics assessment, timing analysis framework, output format template, market size benchmarks by business type and ACV, and common mistakes to avoid, see:

references/full-guide.md