CAC Payback Period Matrix
Find how many months it takes to earn back acquisition cost.
~13 months is reasonable for mid-market/enterprise, but it ties up cash. Lifting margin or ARPA shortens it directly.
Always compute payback on gross margin, not raw revenue, the revenue-basis number flatters you by ignoring the cost of serving the customer.
About this calculator
CAC payback tells you how long a customer has to stay before you've earned back what it cost to acquire them, the clock that determines whether growth self-funds or eats your cash. This calculator computes payback the way it should be computed, on gross-margin-adjusted revenue, and shows you the more flattering revenue-only version side by side so you can see exactly how much margin changes the picture.
How to use it
- Enter your fully-loaded CAC, all sales and marketing cost per customer acquired, not just ad spend.
- Enter monthly revenue per account (ARPA).
- Enter your gross margin percentage.
- Read the margin-adjusted payback in months, alongside the raw revenue-basis payback and a health rating.
Methodology
Margin-adjusted monthly revenue is ARPA times gross margin as a decimal, this is the actual monthly cash a customer contributes after cost-to-serve. CAC payback in months is fully-loaded CAC divided by that margin-adjusted figure.
The revenue-basis payback, shown as a second, unadjusted number, is simply CAC divided by raw ARPA, ignoring gross margin entirely. It's always shorter (more optimistic) than the margin-adjusted figure, and the gap between the two grows as margin shrinks.
Health bands follow common SaaS benchmarks: 12 months or under is graded strong, 12-18 months acceptable for mid-market or enterprise motions, and anything beyond 18 months slow, since that much cash stays locked up per customer before it's recovered.
This tool measures payback on a single blended ARPA and margin figure. It doesn't segment by channel or customer tier, if your paid and organic channels have very different CAC or ARPA, run each separately for an accurate read per channel.
FAQ
The revenue-basis number is what you get if you naively divide CAC by ARPA, ignoring the cost of serving that customer. It's always more flattering. The margin-adjusted number is the honest one, it accounts for the fact that not every revenue dollar is profit you can use to repay acquisition cost.
All sales and marketing spend divided by new customers acquired in the period, including salaries, commissions, tooling, and ad spend, not just media cost. Using only ad spend understates true CAC and makes payback look artificially fast.
It's the common benchmark for SMB/self-serve motions with monthly or annual contracts. Enterprise sales cycles with larger ACVs and multi-year contracts often tolerate 18-24 months, since the deals are bigger and stickier. Judge your number against your own motion, not a single universal bar.
Directly and proportionally, at 100% margin the two numbers in this calculator would be identical; at 50% margin, the margin-adjusted payback is exactly double the revenue-basis figure. Improving gross margin shortens payback just as effectively as cutting CAC or raising ARPA.