Calculators
CAC Payback Calculator
Calculate CAC payback months from acquisition cost, monthly revenue per account and gross margin, with LTV:CAC.
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- Nothing uploaded
The tool
Enter your numbers below. Results update as you type, and nothing leaves your browser.
Everything you enter stays on your own machine. Nothing is sent to us or to anyone else, which you can confirm in your browser network tab.
What people use it for
- Judging sales and marketing efficiency
- Setting a maximum CAC per channel
- Investor reporting
- Deciding between monthly and annual billing incentives
About this tool
What the CAC Payback Calculator does
CAC payback is how many months of gross profit it takes to earn back the cost of acquiring a customer. This calculator divides customer acquisition cost by monthly gross profit per account, and adds lifetime value and the LTV to CAC ratio when you enter churn.
It also works as a customer acquisition payback calculator.
Formula
- Monthly gross profit = revenue per account × gross margin
- CAC payback = CAC ÷ monthly gross profit
- LTV = monthly gross profit ÷ monthly churn
- Share active at payback = (1 − churn)^payback months
Worked example
Using the starting values in the calculator above:
| Input | Value |
|---|---|
| Customer acquisition cost | $1,200 |
| Monthly revenue per account | $150 |
| Gross margin | 80% |
| Monthly churn | 2% |
| Result | Value |
|---|---|
| CAC payback | 10 months |
| LTV : CAC | 5.00x |
| Lifetime gross profit | $6,000 |
| Gross profit per month | $120 |
| Customers still active at payback | 81.7% |
How to read the result
Payback shows how long cash is tied up in growth. Shorter payback lets you reinvest faster without new funding.
Check the share of customers still active at payback. If many leave before then, the average customer never repays its acquisition cost.
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Questions
Questions about this tool
The things clients actually want to know — costs, timelines, ownership and what happens after launch.
Under 12 months is widely considered strong for SMB-focused SaaS; enterprise products often accept 18 to 24 months.
Gross profit, because only margin is available to repay the acquisition cost.
Collecting a year upfront recovers cash immediately, even though the gross-profit payback period stays the same.
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