What is Payback period?
CAC payback period is the time it takes for the gross profit from a customer to cover what it cost to acquire them.
Updated
Payback period is a cash question rather than a profit question, and for a self-funded brand it is often the more important of the two. A customer who eventually contributes ₹2,600 is genuinely valuable, but if that takes fourteen months to arrive, every rupee of growth has to be financed from somewhere in the meantime.
This is why two brands with identical LTV to CAC ratios can have completely different growth ceilings. The one that repays acquisition on the first order can reinvest immediately and compound. The one that repays in month nine is buying growth with working capital it may not have.
The practical rule we use is straightforward. If the first order covers CAC, you can scale as fast as the account allows. If payback lands inside about three months, you can scale steadily. Beyond six months, growth needs to be a deliberate, funded decision rather than something that happens because the ROAS looked acceptable.
How Payback period is calculated
Payback period = CAC ÷ Contribution margin per month from that customer
A worked example
A brand acquires a customer for ₹1,200. That customer contributes ₹840 of gross profit on their first order and reorders roughly every four months.
- CAC = ₹1,200
- First order contributes ₹840 — not yet repaid
- Second order at month 4 contributes another ₹840
Payback at roughly four months, on the second order.
Common mistakes
- Measuring payback on revenue instead of contribution margin, which makes it look about twice as fast as it is.
- Ignoring payback entirely because LTV looks healthy. A profitable customer who repays in eighteen months can still bankrupt a brand.
- Assuming payback is constant while you scale. It usually lengthens as CAC rises.
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