Entrepreneurship

Startup Unit Economics

The three numbers that tell you whether each customer makes or loses you money (CAC, contribution, payback), sized for a company small enough to count on fingers.

  • Beginner
  • 17 min total
  • 12 chapters

What decision this helps you make: Whether to pour fuel on this machine, fix it first, or admit each new customer is quietly costing you money.

What this topic is

Startup unit economics is the per-customer profit machine: what one customer costs to get (CAC), what they contribute after the costs of serving them, and how fast they pay back their acquisition cost.

Why it matters

Growth multiplies whatever the unit is, profit or loss. A business acquiring customers for more than they're worth digs faster the harder it works, and the failure is invisible in revenue graphs until the cash is gone. The whole diagnosis takes three numbers and an afternoon.

Who should learn it

Founders past the first ten customers, deciding whether to scale spending, and anyone whose revenue grows while the bank balance shrinks.

What you will understand

  • CAC, contribution margin, and payback, computed honestly at small scale
  • The LTV trap: why early lifetime-value math flatters
  • The ratios that matter (and their honest early substitutes)
  • What to fix first when the unit is broken

Prerequisites

Common misconception

"We'll make it up on volume." If each customer costs $200 to acquire and contributes $150, volume is the accelerant, not the cure: 10x the customers is 10x the hole. Scale fixes fixed-cost problems; it amplifies unit problems. Know which kind you have before stepping on the gas.