CAC payback period calculator

How many months of gross margin it takes to earn back what you paid to acquire a customer.

CAC payback is the sharpest cash-flow question in acquisition: until a customer has paid back what it cost to win them, every new sale drains cash rather than adding it. Shorter payback means you can reinvest faster and scale without running dry.

The formula

CAC ÷ (monthly revenue per customer × gross margin %)

How to read it

Under ~12 months is comfortable for most subscription businesses; the faster you recover CAC, the more you can reinvest without outside cash.
Use gross margin, not revenue — a euro of revenue that costs you 40 cents to deliver only pays back 60 cents toward CAC.
If payback is long, the lever is rarely just "spend less": rising conversion or margin moves it as much as cutting CAC.

FAQ

Should I use revenue or gross margin?

Gross margin. Payback measures cash recovered, and only the margin on each payment actually pays back the acquisition cost.

What counts as a good CAC payback period?

It depends on your margins and how much cash you can float. We deliberately do not publish a "normal" number — a benchmark from a handful of companies would be misleading. Track your own trend instead.

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