- Use gross profit, not revenue.
- Include salaries and tools in CAC.
- Shorter payback funds faster growth.
Calculate it step by step
A US software company spends $900 in sales and marketing to win a customer paying $150 a month at a 70% margin. Monthly gross profit is $105, so payback is $900 ÷ $105, or 8.6 months.
Build a fully loaded CAC
Include ad spend, agency fees, sales and marketing salaries, commissions and software. Leaving out salaries makes payback look shorter than it is and hides problems when you scale.
Payback and retention together
A 9-month payback works only if customers stay longer than 9 months. If 30 percent leave before month 9, the real payback is longer. Check a retention curve beside payback.
Ways to shorten payback
Raise the first payment with annual plans, cut acquisition cost through referrals and content, or lift margin by reducing delivery cost. Model each lever in the calculator before you commit.
How many months until a customer pays back their cost?
Questions about Unit Economics and Measurement
What is a good payback period?
Under 12 months is common for subscription products. Enterprise sales often accept 18 to 24 months.
How is payback different from LTV to CAC?
Payback measures time. LTV to CAC compares lifetime value with cost.
Should I calculate by channel?
Yes. Channel-level payback shows where to add or cut spend.
Key terms
- CAC payback period
- Customer acquisition cost (CAC)
- Customer lifetime value (LTV)
- Gross margin
- Average revenue per account (ARPA)
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