Free SaaS calculator
CAC Payback Calculator
Use this CAC payback calculator to estimate how many months of gross profit it takes to recover customer acquisition cost. It is a simplified planning metric for SaaS acquisition efficiency.
How to use this calculator
Enter average CAC for the customer segment you are evaluating.
Enter monthly recurring revenue and gross margin for that segment.
Compare payback months against churn risk and available cash runway.
Calculator Inputs
Adjust assumptions and review the result.
Average sales and marketing cost to acquire one customer.
Average monthly recurring revenue from the customer.
Gross margin percentage after hosting, support, and delivery costs.
Export or save this scenario for planning notes.
CAC payback
10 months
CAC / monthly gross profit
Monthly gross profit
$120
Revenue x gross margin
Annual gross profit
$1,440
Monthly gross profit x 12
Interpret this result
Acquisition cost recovery estimate
This scenario estimates how many months of gross profit are needed to recover CAC. Use it as one input in acquisition planning alongside churn, expansion, and cash constraints.
Assumption quality check
- The calculation assumes monthly revenue and gross margin remain steady during the payback period.
- Use segment-specific CAC where possible instead of a broad blended average.
Formula used
CAC payback = CAC / (Monthly revenue x gross margin)
Monthly gross profit
Monthly revenue per customer x gross margin
CAC payback
CAC / monthly gross profit
Annual gross profit
Monthly gross profit x 12
For broader model limits, read the Aura Revenue methodology.
Educational disclaimer
Aura Revenue provides educational forecasting tools and examples only. Outputs are estimates based on user-provided assumptions and should not be treated as financial, legal, tax, accounting, or investment advice.
Common mistakes to avoid
- Using blended CAC when channels or customer segments behave very differently.
- Ignoring gross margin and calculating payback from revenue instead of gross profit.
- Comparing CAC payback without considering churn, expansion, or contract length.
Next planning step
Use this result in a forecast workflow
A single metric is useful, but SaaS planning works best when revenue, churn, acquisition efficiency, and capital efficiency are reviewed together.
CAC Payback FAQ
What is CAC payback?
CAC payback estimates how long it takes for gross profit from a customer to recover acquisition cost.
Why include gross margin?
Gross margin keeps the calculation closer to contribution economics by accounting for delivery costs.
Is shorter always better?
Shorter payback usually reduces cash pressure, but context matters. Contract size, retention, expansion, and market strategy all affect interpretation.