CAC payback calculator
CAC payback calculator
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How it is calculated
CAC payback (months) = CAC ÷ (monthly revenue per customer × gross margin %)
The gross margin matters. The part of each euro that pays for hosting, support and payment fees cannot repay acquisition cost, so dividing by revenue alone makes payback look shorter than it is. This is the version David Skok uses for “months to recover CAC”.
Worked example
Fully loaded CAC is 1,200. A new customer pays 150 a month and gross margin is 80%, so 120 a month of gross profit is available to repay CAC.
1,200 ÷ 120 = 10.0 months. Cut CAC to 600 through a better-converting channel and payback falls to 5. Let the customer pay 100 a month instead and it stretches to 15.
How to read your result
These bands are Mazo’s working thresholds for companies below roughly €1M ARR, built on the guidelines David Skok published. They are not an industry statistic.
| Range | Reading | What it means |
|---|---|---|
| 6 months or less | Excellent | Spend more on the channel that produced it. |
| 6 to 12 months | Healthy | Skok’s guideline is to recover CAC in 12 months or less. |
| 12 to 24 months | Slow, but fixable | Workable with outside funding; tight if revenue funds growth. |
| Over 24 months | Work on this first | Skok suggests improving it once it passes 24 months. |
How to improve it
Raise price before you cut CAC
Payback moves one-for-one with revenue per customer. A 20% price rise cuts payback by about 17% and costs nothing to run. Test it with the next ten prospects before you touch the channel.
Calculate it per channel, not in total
A blended payback hides the one channel that pays back in 4 months and the one that never does. Split new customers by first touch, then divide each channel’s spend by its customers. Cut the worst one first.
Count founder time at a real rate
If your own selling hours are free in the CAC number, the result is flattering and the first hire will break it. Put a salary-equivalent cost on the hours you spend selling.
Shorten the sales cycle
CAC is mostly the hours between first contact and signature. Fewer meetings per deal, a written mutual plan and a clear pricing page all reduce the cost of the same customer.
Common mistakes
Using revenue instead of gross profit
At 80% gross margin the true payback is 25% longer than the revenue-based figure. At 60% margin it is about 67% longer.
Leaving out salaries and tools
CAC is not the ad budget. It is every cost of winning the customer: people, software, agencies, events and referral fees.
Mixing periods
Spend from this quarter divided by customers who signed from last quarter’s work gives a wrong number in either direction. Use a window long enough to cover your sales cycle.
FAQ
What is a good CAC payback period for a SaaS startup?
Should CAC payback use gross margin or revenue?
How is CAC payback different from LTV:CAC?
How do I calculate CAC if I only sell through founder-led sales?
Know the number. Now fix it.
Mazo works out which channel is dragging your payback, builds the plan to fix it, and checks in on it every week. €99 a month, 14 days free.
Start 14-day free trial See all free tools →Written by Madalena Rugeroni, founder of Mazo · Updated 10 November 2026. Benchmarks are credited to whoever published them; where a band is Mazo's own it is labelled as a working threshold. Results are a starting point, not financial advice. Mazo is not affiliated with or endorsed by the sources below.