CAC payback calculator. Months to recover.
Enter AOV, purchase frequency, gross margin, and your blended CAC. See exact months to payback, cumulative contribution by month, and what the bracket says about scaling spend.
Enter your numbers.
Months to payback.
Payback is cash-flow math, not vanity math.
Two brands with identical LTV:CAC ratios can have completely different capital requirements. The brand with a 6-month payback runs lean; the brand with a 20-month payback needs venture funding or an uncomfortable line of credit. Payback tells you the real ask: how long do I need to finance each new customer before they finance themselves?
The formula in this tool: payback = CAC ÷ (AOV × frequency ÷ 12 × margin%). It assumes steady-state monthly purchasing, which is reasonable for most DTC brands past first purchase. Subscription brands have sharper month-one contribution and longer tails; use the LTV calculator for a retention-curve view instead.
Three levers move payback materially. Raising AOV by 15 percent (bundling, add-ons, upsell) cuts payback by roughly 13 percent. Raising frequency by 20 percent (post-purchase flows, replenishment, loyalty) cuts payback by about 17 percent. Raising margin by 5 percentage points (supplier renegotiation, SKU consolidation, reduced shipping cost) cuts payback by the same proportion as the margin delta. Cutting CAC is the fourth lever but often the slowest to move in practice.
Tools in the same cluster: our Blended CAC calculator gives you the right CAC number to feed into this tool. Our LTV calculator gives you the long-horizon view payback alone does not capture. Our Profit calculator shows where the margin lives.
Five answers.
What is CAC payback and why does it matter?
CAC payback is the number of months before a new customer's cumulative gross profit contribution covers the cost of acquiring them. Under 12 months is generally healthy for DTC brands; 6 to 9 months is strong. Payback matters more than raw LTV:CAC ratio for cash-flow planning because it tells you how long your working capital is exposed to each new customer before they turn profitable. A business with a 24-month payback and a 4:1 LTV:CAC ratio can still run out of cash before the second order lands.
How is payback calculated in this tool?
Monthly contribution per customer equals AOV times annual purchase frequency divided by 12, times your gross margin percentage. Payback months equals CAC divided by monthly contribution. The formula assumes steady-state purchasing, which understates early-month contribution for brands with strong first-order bundling. For more precise cohort-aware payback, use the retention curve approach we publish in our LTV calculator.
What is a healthy payback window by business type?
DTC ecommerce: 6-12 months is the healthy range, 4 months and under is exceptional, 18+ months is cash-flow risky. SaaS: 12-18 months is typical, 24 months is the venture rule-of-thumb upper bound. Subscription boxes: 4-8 months because of predictable repeat. Consumables or replenishment: under 6 months because reorder cadence is fast. If your payback falls above these bands, the question is usually about raising contribution (pricing power, AOV, or margin) rather than cutting CAC.
Why use gross margin, not contribution margin?
Gross margin (revenue minus COGS and shipping, as a percent of revenue) is the number that reliably shows up in Shopify and most accounting dashboards, which makes the payback math easier to reason about. Contribution margin (gross margin minus variable marketing and fees) is more accurate for sophisticated unit-economics work but harder to pull cleanly. For a first-look payback read, gross margin is fine; for the board-presentation number, re-run with contribution margin.
Does this calculator save my data?
No. All computation is in-browser. Nothing is sent to a server, logged, or synced. Close the tab and the values are gone. If you want to save a run, the Copy Results button puts a formatted summary on your clipboard.
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