Customer acquisition payback calculator
Estimate months or orders needed to recover acquisition cost.
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How it works
Estimate how long one customer takes to generate enough gross profit or contribution to recover acquisition spending. Enter consistent per-customer revenue and CAC, then choose which margin you use. The schedule begins with acquisition spending at month 0 and adds a constant margin amount at each month end. Stripe explains the profit-based calculation at https://stripe.com/resources/more/what-is-the-cac-payback-period .
A few things to know
Assumes constant revenue, margin and an active customer throughout the recovery period. Excludes churn, expansion, collection delays, upfront or annual billing, time value of money, taxes and costs omitted from your margin. This is margin-based acquisition recovery, not a complete cash-flow or company profitability forecast. All monetary inputs must use the same currency; values are rounded only for display.
Results use your inputs. Keep all money amounts in the same currency.
When to use this tool
Customer acquisition spending is recovered from the margin a customer generates, not from the entire revenue line. This CAC payback calculator estimates the months needed for a constant monthly gross profit or contribution amount to cover the acquisition cost you enter. It also shows the first recovered month end and a downloadable recovery schedule beginning with acquisition at month zero. Use it to compare customer economics or cohort assumptions while remembering that churn, expansion and payment timing can change actual recovery.
- Estimate acquisition recovery for a subscription customer with a known monthly revenue and margin.
- Compare gross-margin and contribution-margin assumptions without confusing either with revenue-only recovery.
- Check how a different CAC or customer price affects unrecovered acquisition spending over a chosen period.
How to use customer acquisition payback calculator
Use matching customer economics
Enter Customer acquisition cost per customer and Monthly revenue per customer for the same customer or comparable cohort, in one currency.
Select the margin definition
Choose Margin basis and enter Margin percent. The selection labels the result; you supply the percentage matching your chosen cost definition.
Review recovery over time
Set Recovery schedule length (months). Compare CAC payback period with First recovered month end, then inspect the unrecovered amount and CSV schedule.
Fractional recovery versus month-end recovery
Inputs
CAC 600; monthly revenue per customer 100; gross margin basis; margin 80%; recovery schedule 12 months.
Result
Monthly gross profit is 80.00. CAC payback is 7.5 months, with first recovered month end at Month 8. At month 7, 40.00 remains unrecovered; after month 8, margin less CAC is positive by 40.00.
What it means
The fractional result assumes margin accrues evenly. If amounts arrive at month end, recovery occurs at the eighth receipt. The customer must remain active and generate the assumed margin through that point.
Common mistakes to avoid
Dividing by revenue alone
Delivery costs consume some revenue. Using the full revenue amount instead of the margin amount makes apparent recovery too fast.
Mixing cohorts
A low CAC from one channel paired with high revenue from another customer segment can produce an unrepresentative result.
Ignoring retention
A short arithmetic payback period is useful only if customers stay active long enough and the margin assumption holds.
Frequently asked questions
Definitions, edge cases, and practical next steps for this tool. Search all tool FAQs ↗
How is CAC payback calculated?
Monthly revenue per customer is multiplied by the margin fraction to produce monthly gross profit or contribution. CAC divided by that monthly amount gives payback in months. The calculation requires positive monthly margin when acquisition cost is positive.
What does changing the margin basis do?
It changes labels and explanatory context between gross profit and contribution. It does not calculate a different percentage or inspect your costs. Enter the correct margin percentage for the selected definition so the comparison reflects the costs you intend to recover.
Why are payback period and first recovered month different?
The period is a fractional estimate with margin accruing evenly. First recovered month end rounds upward for receipts at month end, starting after acquisition. A 7.5-month estimate therefore becomes recovery at month 8 under that timing convention.
What happens if CAC is zero?
The result is immediate recovery at month zero because there is no acquisition amount to repay. This remains true even if revenue or margin is zero. It does not establish that future revenue is certain or that the customer is profitable overall.
What if revenue or margin is zero?
A positive CAC cannot be recovered from a zero monthly margin amount. The calculator reports no payback at those inputs and keeps the acquisition cost unrecovered in the schedule. Negative margins are outside this tool’s accepted range.
Does this account for churn or expansion?
No. Monthly revenue and margin remain constant and the customer stays active throughout the schedule. Compare that assumption with actual retention and expansion data. A customer leaving before recovery can make the constant-revenue estimate unsuitable.
Can I use annual prepaid subscriptions?
You can enter a consistent monthly revenue equivalent for a margin-based comparison, but the schedule will not reproduce upfront cash receipts. Annual billing and delivery costs have different timing. Build a separate cash-flow plan if cash recovery is your question.
Is there a universally good payback period?
This calculator supplies no universal benchmark. Interpret the result alongside available cash, retention, margin reliability and business model. Compare like-for-like cohorts over time; a faster estimate with unreliable revenue assumptions can be less useful than a slower, well-supported one.
Explore the topic in the blog
Sources and method
Use the references below to check definitions and platform guidance. The model’s scope and limits are explained above. Read our editorial standards.