SaaS CAC Payback Speed Calculator

Pair CAC with per-account MRR to see exactly how many months it takes to recover acquisition spend at your stated gross margin, while estimating lifetime gross profit based on churn. It’s a fast gut-check for board decks and pipeline prioritization.

Total blended marketing + sales cost to land one customer.
Contracted monthly recurring revenue expected from the account.
Optional. Defaults to 80%. Applies the service gross margin to MRR.
Optional. Defaults to 12%. Converts into lifetime months for gross profit.

Illustrative efficiency benchmark—reconcile results with your finance system before reporting to investors.

Examples

  • CAC of $8,400, $1,200 in MRR, 82% gross margin, and 10% annual churn ⇒ CAC payback occurs in 8.54 months • Monthly gross contribution per account: $984.00 USD • Expected lifetime gross profit: $118,080.00 USD over 120.00 months • Payback consumes 7.11% of projected lifetime value.
  • $3,100 CAC and $450 in MRR with default margin/churn ⇒ CAC payback occurs in 8.61 months • Monthly gross contribution per account: $360.00 USD • Expected lifetime gross profit: $36,000.00 USD over 100.00 months • Payback consumes 8.61% of projected lifetime value.

FAQ

Why use gross margin instead of pure MRR?

Gross margin excludes hosting, support, and third-party pass-through costs so the payback period reflects the cash you truly recover from the account.

What if churn is expressed monthly?

Convert it to an annualized percentage before entering it here. For example, 1% monthly churn is roughly 11.4% annually.

Can I model sales-assisted vs. product-led CAC separately?

Yes. Run the calculator twice with CAC and MRR values for each motion to compare which cohort recovers cash faster.

Additional Information

  • Result unit: months to recover CAC plus contextual gross profit figures shown in U.S. dollars.
  • Lifetime months convert the annual churn percentage into a straight 1/churn estimate capped at 10 years to avoid division by zero.
  • Gross margin defaults to 80% so the calculator reflects typical infrastructure + support costs without additional inputs.

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