CAC Payback Period Calculator

Estimate how many months are needed to recover acquisition cost from gross-profit dollars, with an optional churn adjustment for conservative planning.

Fully loaded sales and marketing spend per new customer.
Monthly recurring revenue recognized per customer.
Gross margin percentage applied to recurring revenue.
Optional. Defaults to 0%. Applied as a survival factor to gross profit recovery.

Educational estimate for planning. Finance teams may use cohort- or channel-specific payback frameworks.

Examples

  • $8,000 CAC, $1,200 monthly revenue, 78% gross margin, 0% churn adjustment ⇒ CAC payback period: 8.55 months | Monthly gross profit recovery: $936.00
  • $11,500 CAC, $1,450 monthly revenue, 82% gross margin, 2.5% churn adjustment ⇒ CAC payback period: 9.92 months | Monthly gross profit recovery: $1,159.73

FAQ

Why apply gross margin instead of revenue directly?

Payback should be measured on gross profit, not top-line revenue, because only margin dollars can recover acquisition spend.

What churn adjustment should I use?

Start with 0% for simple reporting, then test conservative cases using recent monthly logo or revenue churn estimates.

Is lower payback always better?

Usually yes for cash efficiency, but compare with retention quality and net revenue expansion to avoid underinvesting in growth.

Additional Information

  • Primary output is payback period in months with two decimal places using en-US number formatting.
  • Gross margin input is required and bounded from 0% to 100% to keep results physically meaningful.
  • Monthly churn adjustment is optional and defaults to 0%, allowing conservative scenarios without breaking baseline calculations.
  • This model assumes constant monthly revenue and margin. Use cohort-level curves when expansion or contraction is material.

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