Free tool
What paid acquisition really costs per customer
This works forward from ad spend through clicks, signups, and close rate to a real cost per customer, then checks that figure against your gross profit. Paid acquisition fails quietly when cost per customer drifts above what a customer is worth, and the arithmetic makes that visible early.
Last reviewed 27 August 2026
Result
Cost per customer
$1,125
Payback on gross profit
4.7 months
The funnel
| Stage | Volume | Cost each |
|---|---|---|
| Clicks | 2,222 | $5 |
| Signups | 89 | $113 |
| Customers | 8.9 | $1,125 |
This clears the usual twelve-month payback guideline, so the channel can absorb more budget provided the rates hold at higher spend.
How this works
What the numbers mean.
- 01Spend divided by cost per click gives clicks. Everything after that is your funnel, so the output is only as good as the two conversion rates you enter.
- 02Cost per customer is total spend divided by customers, which correctly attributes the cost of everyone who did not convert.
- 03Payback compares that against monthly gross profit. Paid acquisition is the channel where getting this wrong is most expensive, because spend scales instantly and the mistake compounds daily.
Assumptions and limits
- Rates rarely hold as spend rises. Doubling budget usually raises cost per click and lowers conversion as you reach a colder audience.
- This is a single-touch model. It ignores that most B2B buyers touch several channels before converting.
- Ad platform reporting tends to over-attribute. Compare against your own signup data.
Questions about this tool
Why does my real CAC exceed the platform's reported figure?
Because ad platforms attribute generously to themselves and typically exclude the spend that produced no conversion at all. Calculating from total spend divided by total customers, as this tool does, gives a figure that reconciles with your bank account.
Which input should I improve first?
Almost always the click to signup rate. It is the cheapest to change, it compounds through everything downstream, and it is usually the weakest number in the funnel. Reducing cost per click is harder and lowers volume.
Is paid worth it at seed stage?
Sometimes, but it is the channel most likely to waste an early budget. Paid amplifies a message that already converts, it cannot manufacture one. If you have not yet found the message organically, paid tends to buy an expensive education.
This tool is free and there is nothing to sign up for. If you would rather have the work done than calculate it, that is what Zway does.