CAC payback
CAC Payback Period Calculator.
CAC payback period is the number of months a customer has to stick around to pay back what you spent acquiring them. The formula divides your customer acquisition cost by the monthly gross profit each customer produces. For an indie SaaS at $49 ARPU, 90 percent gross margin, and a $100 CAC, payback lands at 2.3 months – well inside the healthy zone. The standard rule of thumb is: under 12 months is healthy, 12 to 18 months is yellow, above 18 months is a channel that bleeds cash and cannot scale. If your payback is longer than your average customer lifetime, the channel is unprofitable at any volume.
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Formula
Payback (months) = CAC / (ARPU × Gross Margin %)Calculator
Inputs
Fully-loaded: ad spend plus sales-rep compensation plus marketing salaries, divided by customers acquired in the same window.
Result
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Frequently asked
- What is a healthy CAC payback period for indie SaaS?
- Under 12 months is the standard threshold for sustainable growth. 12 to 18 is workable but constrains how fast you can scale paid channels. Above 18 months and the channel is likely unprofitable.
- Should I include sales-team salaries in CAC?
- Yes, for the honest version. CAC is the fully-loaded cost of acquiring one customer: ad spend, sales-rep compensation, marketing-team salaries, free-trial infrastructure, divided by customers acquired in the same window.
- How is CAC payback different from LTV-to-CAC?
- Payback measures time-to-recover; LTV-to-CAC measures total profit over lifetime. Payback tells you if a channel scales without running out of cash; LTV-to-CAC tells you if the channel is profitable at all. Healthy SaaS clear both bars.
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- Monthly Churn Cost Calculator – How much revenue evaporates every month while you focus on acquisition? The number that gets retention on the roadmap.
- Post-Launch Revenue Projector – Where does your MRR actually land in twelve months given your real churn and acquisition rate? See the curve.
- Pricing Power Calculator – What happens to LTV, payback, and LTV-to-CAC if you raise your price 50 percent? Side-by-side answer.