WordPressA payback window answers one question: how long until the margin from a group of new customers covers what it cost to win them. It is measured in days or months, and it is only as good as the margin and repeat data behind it.
What it tells you
- How long cash stays out of the business for each new customer. A two-month window and a nine-month window need different budgets, even at the same ratio.
- Whether the acquisition cost fits the margin the store really keeps. Use contribution margin, not revenue, or the window will look too short.
- How much repeat purchases matter. A window that closes only because of repeat orders is a bet on those repeats.
What it does not tell you
- It does not tell you whether an ad is good or bad on its own. It tells you how fast a cohort returns its cost.
- It is an estimate until the cohort is mature. A window built on one month of repeat data is partly a guess, so label it as estimated.
How to read it
- Build the window by cohort, by the month the customers were acquired, and read each cohort against the same line.
- Show the share of cohorts that have paid back at each point, not one average.
- Read it next to the break-even line and the repeat purchase rate, so the cash view and the margin view agree.
Made-up scenario: a store's first-month cohorts paid back their acquisition cost in about seven weeks on contribution margin. A repeat purchase estimate based on two months of data pulled that to five weeks. The team reported the seven-week figure as measured and the five-week figure as an estimate.
