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How to calculate customer acquisition payback period

2026-05-20 14:37 · Paid Marketing

Learn the CAC payback period formula, see a simple example, and understand how payback period helps judge acquisition quality.

Customer acquisition payback period shows how long it takes to recover the cost of acquiring a customer.

The basic formula is:

Payback period = CAC / monthly gross profit per customer

For example, if customer acquisition cost is $150 and monthly gross profit per customer is $30, the payback period is 5 months. That means the customer needs about five months of gross profit before acquisition cost is recovered.

To calculate monthly gross profit, multiply monthly revenue per customer by gross margin. If monthly revenue is $50 and gross margin is 60%, monthly gross profit is $30.

Payback period is useful because LTV can look attractive while cash recovery is still slow. A customer may be valuable over two years, but a business may not want to wait too long to recover acquisition spend.

Use the Payback Period Calculator at /tools/payback-period-calculator for quick checks. Then compare the result with CAC, LTV, CPA, ROAS, and ROI to judge whether acquisition is efficient and sustainable.