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CAC payback calculator
Every customer starts as a loss. Find out how many months it takes before they turn profitable.
CAC payback period
10.2 months
Healthy: under 12 months is the usual benchmark for SaaS.
Monthly gross profit per customer
$39.2
ARPU multiplied by gross margin
What is CAC payback and why cash-conscious founders track it
Customer acquisition cost is what you spend — ads, sales time, onboarding — to win one customer. CAC payback answers a blunt question: how many months of that customer's revenue does it take to earn the money back? The formula divides CAC by the monthly gross profit per customer, which is ARPU multiplied by your gross margin. Using gross profit rather than raw revenue matters: a dollar of ARPU at 80 percent margin repays debt four times faster than the same dollar at 20 percent.
The common benchmarks: under 12 months is healthy for SaaS, 12 to 24 months is workable if retention is strong and capital is available, and beyond 24 months you are effectively lending money to your growth channel and hoping churn does not call the loan. Early-stage companies should aim even lower, because their churn estimates are unreliable and their cash runway is short.
Payback is the cash-flow twin of the LTV to CAC ratio. LTV to CAC tells you whether a channel is profitable eventually; payback tells you how much cash you need to finance growth in the meantime. A channel with a great ratio but a 30-month payback can still sink a bootstrapped company. That is why payback is often the better operating metric: it is measurable within a quarter, while LTV takes years to observe.
To shorten payback you have three levers, in order of typical impact: raise prices or expand accounts early, cut acquisition spend that does not convert, and push customers to annual prepay — which collapses payback to day one.