CAC Payback Period
The CAC payback period is the number of months of gross margin a customer must pay to cover what you spent to acquire them.
Updated October 1, 2026
The CAC payback period is the number of months a customer takes to earn back what you spent to acquire them, counted in gross margin. The shorter it is, the sooner you can spend that money on the next customer.
How to calculate CAC payback
CAC payback = CAC ÷ (monthly ARPA × gross margin)
Divide CAC by the monthly gross profit from one customer. With a CAC of $1,200, monthly ARPA of $100, and an 80% gross margin, each customer earns $80/month in margin. Payback is $1,200 ÷ $80 = 15 months. Using revenue instead of margin gives 12 months, which is too optimistic.
Why it matters
Two companies can have the same LTV:CAC ratio and very different cash needs. A company that recovers CAC in 6 months can reinvest three times as often as one that takes 18 months. That is why investors look at payback next to the ratio.
Rough benchmarks for subscription businesses:
- Under 12 months. Strong, especially for self-serve products.
- 12 to 18 months. Typical for many B2B companies.
- Over 24 months. A heavy cash strain. Customers who churn before payback never cover their acquisition cost.
Higher margins and more expansion revenue shorten payback without cutting acquisition spend.