Payback Period

Payback period is the number of months it takes to recover a customer's acquisition cost from the gross profit they generate.

Payback period answers a cash question, not just a profitability question: how long is money tied up in this customer before they start paying for themselves? A business can have excellent LTV:CAC economics on paper while still running into cash flow trouble if payback periods are long and the business is growing fast — every new cohort of customers requires fresh cash outlay before the previous cohort has paid it back.

There's no single universal "good" number, but a commonly cited operator and investor rule of thumb treats under 12 months as capital-efficient, 12–18 as workable with adequate runway, and beyond 18–24 months as a sign the business is effectively financing its own growth. Capital-intensive or heavily subsidized marketplace businesses routinely run longer paybacks by design, so context matters more than the raw number.