CAC Payback Formula
The CAC Payback Formula helps you determine how many months it takes for the gross profit generated by a new customer to cover their initial acquisition cost, a vital metric for cash flow and marketing efficiency.
Formula
Copy the exact expression or work through it step by step below.
CAC Payback Months = Customer Acquisition Cost / Monthly Gross Margin Per Customer Variables
CPM
CAC Payback Months
The cac payback months value plugged into the cac payback calculation.
CAC
Customer Acquisition Cost
The cost-side input that anchors the cac payback math.
MGMC
Monthly Gross Margin Per Customer
The monthly gross margin per customer value plugged into the cac payback calculation.
Step By Step
- 1
Set the baseline case with the real calculator inputs.
CAC = $2,400, Arpu Monthly = 129, Gross Margin Percent = 75.0%, Target Payback Months = 12
- 2
Translate rates, periods, and cash values onto the same footing before combining them.
Keep the cac payback assumptions consistent instead of mixing monthly and annual views.
- 3
Apply the formula and read the first calculator outputs, not just the headline assumption.
The calculator lands with monthly gross profit at $96.75 and estimated ltv24m at $2,322.
- 4
Run one changed scenario so the formula is stress-tested before it is trusted.
The cac payback calculator page is the fastest way to compare that second case.
Worked Example
CAC Payback sample case
CAC
$2,400
Arpu Monthly
129
Gross Margin Percent
75.0%
Target Payback Months
12
CAC Payback Months = Customer Acquisition Cost / Monthly Gross Margin Per Customer using cac $2,400, arpu monthly 129, gross margin percent 75.0%, target payback months 12.
The calculator lands with monthly gross profit at $96.75 and estimated ltv24m at $2,322.
Common Variations
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Sources & References
- CAC Payback Period: The Most Important SaaS Metric You Aren't Tracking — Baremetrics
- The Ultimate Guide to CAC Payback Period — ProfitWell
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