4 months is the example result. Read it using the units and relationship stated below.
Estimate the months needed to recover acquisition cost from monthly gross margin per customer. This is a steady monthly contribution model.
Check how long acquisition cost takes to recover
The calculation divides CAC by the supplied monthly margin. It assumes that contribution repeats at that level and does not build a cohort cash-flow schedule.
When to use this result
Use it before committing to an acquisition budget. Compare the recovery period with retention and the cash available to fund customers until their contribution repays the original spend.
Check before you act
Revenue is not the same as monthly gross margin. A customer who leaves early may never reach the mathematical payback point.
Example with the supplied inputs
Customer acquisition cost: 300; Monthly gross margin per customer: 75. Result: 4 months. The values are illustrative.
Compare one changed input
Customer acquisition cost changes from 300 to 330. The result becomes 4.4 months. All other inputs remain fixed.
Calculation rule
Result = (([Customer acquisition cost]) ÷ ([Monthly gross margin per customer]))
Inputs and output
| Input | Example value | Entry convention |
|---|---|---|
| Customer acquisition cost | 300 | Use customer acquisition cost on the currency and period basis shown by the formula. Keep gross amounts, net amounts and unit amounts distinct; the page does not fetch a price or exchange rate. |
| Monthly gross margin per customer | 75 | Enter monthly gross profit per customer as a currency amount, not a percentage. Use the same currency as customer acquisition cost. CAC divided by this monthly amount gives payback in months. |
Output: 4 months is the example result. Read it using the units and relationship stated below. Use the formula to distinguish a cash amount, count, percentage or ratio.
How to use the page
Collect the inputs
Gather Customer acquisition cost, Monthly gross margin per customer. Use one period and the units shown in the form.
Run the calculation
Enter the values and select the action. The calculation rule above explains how the inputs produce the result.
Compare a scenario
Change Customer acquisition cost on its own, keeping the other inputs fixed. Read both results before changing another assumption.
Worked example
With the example inputs listed above, the result is 4 months.
Change Customer acquisition cost from 300 to 330 while keeping every other value fixed. The result becomes 4.4 months. This comparison isolates that input; it does not forecast how other variables will respond.
Check the stated formula, units and limits before using the result in a decision.
Keep the displayed formula, input units and model scope with the result. Corrections or questions can be sent through the request section on this page.
Content updated: October 11, 2026