What is the CAC payback period?
The CAC payback period is the number of months of gross profit from a new customer needed to recover what it cost to win them. It turns acquisition cost into a time measure that can be set against cash plans and contract terms. A long payback means the company funds each new customer for longer before it earns anything back.
Why it matters to a revenue leader
Payback matters most when cash is tight. A venture-backed company with a long payback burns more cash for each dollar of growth. In a services company, the same idea applies to a new territory or a new seller, measured as the months until its gross profit covers what it cost. If customers tend to leave before payback, growth loses money however strong bookings look.
How to calculate it
CAC payback (months) = CAC divided by (monthly recurring revenue per new customer times gross margin). A common mistake is using revenue instead of gross profit, which makes payback look shorter than it is.
Example
Fictitious numbersA security monitoring company spends $240,000 a quarter on sales and marketing and wins 40 new accounts, so CAC is $6,000. Each account pays $500 a month at 60 percent gross margin, or $300 of gross profit a month. Payback is 20 months.
"How many months does it take a new customer to pay back what we spent to win them, and how many leave before then?"
Sources
- CAC Payback Period (Corporate Finance Institute) checked 9 Oct 2026