Analytics and measurement
CPA Calculator: Cost per Acquisition
Work out what each lead, sign-up or sale costs you, and whether that cost is within what a conversion is worth.
Runs in your browser; nothing is uploaded. · Free, no account · 1 min
The most you can pay per conversion and still break even.
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How to use
- Enter the spend for the period.
- Enter the conversions it produced.
- Add the gross profit per conversion, or a target CPA, if you have one.
- Read the CPA and the checks against your target.
What it checks and how it works
CPA = spend / conversions. Google Ads describes cost per acquisition in its Target CPA help page as the average cost per conversion. The tool also shows conversions per 1,000 spent, and the margin left per conversion after CPA when you give a gross profit per conversion.
CPA can be compared only when the conversion is defined the same way: a lead, a trial and a purchase cost very different amounts. State whether spend includes agency fees and creative cost. With no conversions the CPA is undefined, so the tool reports the spend and waits for data. A CPA above the gross profit on one sale can still pay off if customers buy again, which is what the CAC payback tool tests.
Sources
- Google Ads Help: About Target CPA bidding opened 29 Oct 2026
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Questions
About this tool
CPA is the cost per conversion of any kind, such as a lead or a sign-up. CAC is the cost of winning a paying customer, usually counting all sales and marketing spend. They coincide only when the conversion is a customer's initial purchase and the spend is the same.
The most you can pay per conversion and still break even is the gross profit it brings. Set the target below that so the ads leave room for other costs and some profit.
It is common, because the cheapest conversions are won first. Watch the CPA of the extra spend, not only the average, before raising a budget.
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