CAC Payback Period Calculator

The CAC payback period tells you how long it takes to earn back the cost of acquiring a customer, and this calculator works it out from your unit economics. It is one of the most practical efficiency metrics in SaaS, because it speaks directly to cash flow: the faster you recover what you spent winning a customer, the sooner that customer becomes profitable and the less cash you tie up funding growth. The payback period is the customer acquisition cost divided by the monthly gross profit each customer generates, giving an answer in months. Using gross profit rather than revenue keeps it honest, since servicing the customer has a cost. A short payback, well under a year, means your growth is self-funding and cash-efficient; a long payback, beyond eighteen months or two years, means you wait a long time to recoup each customer, which strains cash and raises the risk that they churn before paying you back. This calculator makes it clear. You enter the customer acquisition cost, the average monthly revenue per account, and your gross margin, and it returns the payback period in months, the monthly gross profit per customer, and a verdict. The results update as you type. Use it to assess acquisition efficiency, to set payback targets, or to compare channels and segments. The payback period is CAC divided by the product of monthly revenue per account and gross margin. A common benchmark is under twelve months for healthy SaaS, with under six months considered excellent and over eighteen months a concern. Read it alongside the LTV-to-CAC ratio: a strong ratio earned only over a very long payback can still be a cash-flow problem, because you are profitable in the long run but starved of cash in the short. Fast payback is what lets a business grow without constantly raising money.

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Payback = CAC / (monthly revenue per account x gross margin). Under 12 months is healthy, under 6 excellent, over 18 a concern. Uses gross profit, not revenue.