The Two Numbers
The only metrics that determine whether your startup lives or dies
by Lech Kaniuk
Last updated: April 2026
Two metrics. Every investor will ask. Most founders fumble.
Every investor will ask about your unit economics. Most founders fumble the answer โ not because their business is broken, but because they don't speak the language. LTV and CAC are not accounting concepts. They're a map of whether your business model actually works. This book walks through the math, the interpretation, and what to do when the numbers aren't where you need them to be.
Table of contents
- โ Why I wrote this book Free
- 1 Why two numbers rule everything Free
- 2 The slide that doesn't exist Free
- 3 Defining the core metrics
- 4 Benchmarks and ratios that matter
- 5 Introducing the Value Lens
- 6 Understanding and increasing LTV
- 7 Understanding and reducing CAC
- 8 The LTV-CAC Growth Map
- 9 The X-Ray
- 10 Simulation-driven strategy
- 11 The 90-day installation
- 12 The LTV-CAC Operating System
- 13 Beyond the metrics
- 14 Tools, templates, and tech
- 15 Building the Two Numbers Slide
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What readers say
"The clearest explanation of unit economics I've read. Every founder should have this before their Series A prep."
"I wish I had read this before my seed round. Would have saved two months of confusion."