CAC Payback Calculator
How many months until a new customer pays back what it cost to win them. Under 12 is healthy. Over 18 means you’re financing growth you can’t afford.
What this number actually means
CAC payback is the simplest cash-flow question in your business: how long until each new customer pays back what it cost to land them. Under it sit two harder questions — how fast can you reinvest in growth, and how much runway do you need to keep adding customers.
Under 12 months, you have a flywheel. The customer you closed in January is funding the one you close in October. Over 18 months, you’re running an unfunded line of credit to yourself — especially dangerous for bootstrapped or lean companies, where there’s no fresh capital coming in to bridge the gap.
One caveat the calculator doesn’t show: payback assumes the customer stays. If churn is high, the real payback is worse than the number above — sometimes by a lot. A 14-month payback with 5% monthly churn isn’t a 14-month payback, it’s a hole. If your number looks fine and growth still feels stuck, churn is the next place to look.
This is one number. Your whole growth system has seven.
The Punch Diagnostic scores your business across the seven systems that break between $1M and $5M ARR — CAC and the six others that decide whether the payback story is the right one to be telling.