Plainhub
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CAC calculator

Customer acquisition cost from your sales and marketing spend, plus how many months it takes to earn it back. No signup, nothing stored.

CAC
€600
per new customer
Total spend
€27,000
sales + marketing
CAC payback
6.3
months to recover

Under 12 months payback is the healthy SaaS range: the customer covers their own acquisition cost inside a year and starts funding the next one.

The CAC formula

CAC is total acquisition spend over customers won, and payback is CAC over monthly gross profit:

CAC         = (sales + marketing spend) / new customers
CAC payback = CAC / (revenue per customer x gross margin)

CAC on its own is only half the picture. A 600 euro CAC is excellent if customers pay 200 euros a month at high margin, and dangerous if they pay 30. That is why the payback period matters more for a startup: it converts CAC into the one currency you are short of, which is time. Pair this with the LTV calculator to see the full unit economics, and read the SaaS metrics that matter.

Common questions

What is the CAC formula?

CAC = (sales spend + marketing spend) / new customers acquired in the same period. If you spent 27,000 euros across sales and marketing and won 45 customers, your CAC is 600 euros.

What should be included in customer acquisition cost?

Everything spent to win customers: ad spend, content and SEO tools, sales salaries and commission, and the software those teams use. Leave out costs of serving existing customers, which belong in cost of goods sold, not CAC.

What is a good CAC payback period?

Under 12 months is the healthy SaaS benchmark. It means a customer covers the cost of acquiring them within a year in gross profit, then starts funding the next one. For an early startup, payback matters more than the LTV:CAC ratio because it is measured in cash and time you actually have.

What is the difference between CAC and CPA?

CPA (cost per acquisition) usually means cost per lead or signup, including free ones. CAC is cost per paying customer. CAC is always the higher and more meaningful number for a subscription business.

CAC only matters against your runway

A 14-month payback is fine with two years of runway and reckless with eight months. Plainhub keeps acquisition spend, payback and runway in one live model so you can see the trade-off.

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