Payback Period Calculator
It takes 8.2 months to recover $320 per customer.
What is Payback period?
CAC payback period is the number of months it takes to earn back the cost of acquiring a customer, paid out of the gross profit that customer brings in each month.
It is worked out as customer acquisition cost (CAC) divided by monthly gross profit per customer, where monthly gross profit is monthly revenue times gross margin. The shorter it is, the faster your acquisition spend comes back as cash.
Payback measures speed, not size. Two businesses can share the same LTV:CAC ratio yet have very different paybacks, and the one that recovers cash sooner can reinvest and grow faster.
How to calculate Payback period
Payback = CAC ÷ (Monthly revenue × Gross margin)
- Take your acquisition cost. The all-in cost to win one customer. The example uses 320.
- Find monthly revenue per customer. What a customer pays you each month. The example uses 49.
- Apply gross margin. Multiply monthly revenue by gross margin to get monthly gross profit. 49 at an 80% margin is 39.20.
- Divide CAC by monthly gross profit. 320 divided by 39.20 is about 8.2 months to recover the cost.
Worked example
A customer costs 320 to acquire, pays 49 a month, at an 80% gross margin.
| Customer acquisition cost | $320 |
|---|---|
| Monthly revenue per customer | $49 |
| Gross margin | 80% |
| Result | 8.2 months · Healthy |
Monthly gross profit is 39.20, so it takes about 8.2 months to recover the 320 acquisition cost. That clears the 12-month convention, and by the end of year one each customer has returned roughly 150 in profit.
What is a good Payback period?
Under 12 months is the common rule of thumb for subscription businesses, the level at which the calculator marks payback healthy. It is a convention, not a law.
| Payback period | Read |
|---|---|
| healthy under 12 months | The usual target for most subscription models |
| watch 12 to 18 months | Workable with strong retention and enough cash |
| strained over 18 months | Heavy on cash; only safe with very low churn or high LTV |
The right payback depends on your cash position and model: low-ticket products often aim well under 12 months, while high-value enterprise deals can justify longer. Judge it against your runway, not a single number.
How to improve Payback period
- Lower CAC by tightening targeting and shifting budget to channels that convert cheaply.
- Raise the monthly price or move customers to higher tiers so more comes back each month.
- Protect gross margin, since payback is recovered from profit, not revenue.
- Reduce early churn so customers survive long enough to actually pay back their acquisition cost.
Frequently asked questions
- What is CAC payback period?
- CAC payback period is the number of months it takes to recover the cost of acquiring a customer from the gross profit that customer brings in. A shorter payback means you get your acquisition spend back faster. It is acquisition payback, not the capital-budgeting payback used for one-off investments.
- How do you calculate CAC payback period?
- Divide customer acquisition cost by the monthly gross profit per customer, where monthly gross profit is monthly revenue per customer times gross margin. For example, a 320 CAC against 49 monthly revenue at an 80% margin is 39.20 monthly gross profit, so payback is about 8.2 months.
- What is a good CAC payback period?
- Under 12 months is a common rule of thumb for subscription businesses, but it is a convention, not a law. Low-ticket, high-volume products often aim well under 12 months, while higher-value enterprise deals can justify longer. Judge it against your cash position and growth plans.
- Why does gross margin matter to payback?
- Because you recover acquisition cost out of gross profit, not revenue. Ignore margin and you overstate how fast a customer pays back. At a 49 monthly price, an 80% margin returns 39.20 a month toward CAC, while a 50% margin returns only 24.50, stretching the payback.