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CAC Payback Period Calculator

Calculate how many months it takes to recover customer acquisition cost.

About CAC Payback Period Calculator

Payback uses gross profit rather than revenue, because only the margin is available to repay acquisition. Comparing payback against average customer lifetime shows whether the model works at all. Payback period determines how much working capital growth consumes: a twenty-four month payback means every new customer is cash-negative for two years regardless of lifetime value.

Formula

CAC Payback Period

Payback months = CAC ÷ (monthly revenue × gross margin)

payback
Months of gross profit needed to recover acquisition cost
average lifetime
The reciprocal of the monthly churn rate

Worked example

With the default values below, CAC Payback Period Calculator returns Payback Period of 9.615. Change any input above and every figure here is recalculated in your browser.

Inputs used

Customer acquisition costminimum 0
900
Monthly revenue per customerminimum 0.01
120
Gross marginaccepts 0.01–100 %
78 %
Monthly churn rateaccepts 0–100 %
2.5 %

Results

Payback Period
9.615 months
Monthly Gross Profit per Customer
$93.60
Average Customer Lifetime
40.00 months
Lifetime Value to CAC Ratio
4.160 x
Verdict
Healthy — payback within twelve months

Step by step

  1. 1Values used
  2. 2CAC Payback Period
  3. 3Payback Period= 9.615 months
  4. 4Monthly Gross Profit per Customer= 93.60
  5. 5Average Customer Lifetime= 40.00 months
  6. 6Lifetime Value to CAC Ratio= 4.160 x
  7. 7Verdict= Healthy — payback within twelve months

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is CAC Payback Period calculated?

Payback months = CAC ÷ (monthly revenue × gross margin) Payback uses gross profit rather than revenue, because only the margin is available to repay acquisition. Comparing payback against average customer lifetime shows whether the model works at all.

Why does CAC Payback Period matter?

Payback period determines how much working capital growth consumes: a twenty-four month payback means every new customer is cash-negative for two years regardless of lifetime value.

What values do I need to enter?

This calculator takes 4 inputs: Customer acquisition cost, Monthly revenue per customer, Gross margin, Monthly churn rate. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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