Definition · also called CAC payback, CAC payback period, months to recover CAC
Payback period (in SaaS, CAC payback) is the number of months a new customer takes to repay the cost of acquiring them, out of the gross profit they generate.
It matters more than LTV:CAC for bootstrapped founders: a great lifetime value is no help if you run out of cash waiting to collect it.
Payback period formula
CAC payback (months) = CAC ÷ (ARPU × gross margin)
- Use monthly ARPU and gross margin as a fraction (0.8 for 80%).
- Annual prepayment shortens cash payback dramatically: a customer who pays for a year upfront repays CAC on day one if CAC is below the annual price.
- The general finance definition of payback period, months or years for an investment's cash flows to repay its cost, uses the same logic.
Worked example
You spend $2,400 on ads and win 20 customers: CAC = $120. ARPU is $25/month at 80% gross margin = $20/month of gross profit.
- Payback = $120 ÷ $20 = 6 months
If half of new customers choose a $240/year plan paid upfront, those customers repay their CAC immediately.
Payback period benchmarks
| Benchmark | Value | Source |
|---|---|---|
| CAC payback, best SaaS businesses | 5–7 months | David Skok, For Entrepreneurs |
| Payback where SaaS profitability weakens | beyond 12 months | David Skok, For Entrepreneurs |
Payback period in practice: how indie makers use it
Bootstrapped makers keep payback short by keeping CAC low or getting paid upfront:
Grows products mainly with paid ads, which only works when payback is short; Talknotes reached about $7.5K MRR in 11 months and sold for $200,000. (source: jeannen.com)
Opened Testimonial.to with $199 lifetime deals, so cash arrived upfront; 30 sold in the first two weeks. (source: creatoreconomy.so)
Plausible reached $1M ARR with no paid marketing: when cash CAC is near zero, payback is immediate. (source: plausible.io)
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Frequently asked questions
How do you calculate CAC payback period?
Divide customer acquisition cost by monthly gross profit per customer (ARPU × gross margin). $120 CAC ÷ $20 monthly gross profit = 6 months.
What is a good CAC payback period?
Under 12 months is the usual SaaS benchmark, and the best companies recover CAC in about 5–7 months according to David Skok. Bootstrapped founders often aim even shorter.
How do annual plans affect payback?
Annual prepayment brings a year of revenue forward, so cash payback can be immediate even when the gross-profit payback is several months.
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Maker examples are paraphrased from the cited sources and from each maker's IndieMakerList profile; revenue is self-reported unless marked verified. Spotted an error? Tell us.