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Paid Advertising

CPA Calculator

Calculate cost per acquisition from spend and conversions. Enter your numbers below to get an instant result.

Updated: October 5, 2026•No sign-up required•Calculation runs in your browser

Calculate CPA

Ad spend for the selected period.
Completed conversions attributed to that spend.
Cost per acquisition
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How to use this cpa calculator

Enter values from the same reporting period and use consistent definitions. Then select Calculate. The tool performs the calculation locally in your browser and shows the result immediately.

Formula

CPA = Advertising Spend ÷ Conversions

Example

A campaign that spends $2,400 and generates 30 purchases has an $80 CPA.

What this metric tells you

CPA is often easier to connect to profitability than ROAS when order values are stable. It tells you the average advertising cost required to generate one conversion.

How to interpret the result

  • Compare actual CPA with your maximum profitable CPA.
  • Check whether the conversion action is a sale, lead or another event before interpreting the number.
  • When order values vary materially, use CPA alongside ROAS and contribution margin.
Important: Calculators provide estimates based on the inputs you supply. They do not replace platform reporting, accounting records, tax advice or professional financial analysis.

Frequently asked questions

Is CPA the same as CAC?

They can be similar, but customer acquisition cost may include broader sales and marketing costs, while ad-platform CPA often reflects only media spend divided by attributed conversions.

Can CPA be higher than product profit?

Yes, but that may be unprofitable on the first order unless repeat purchases or other economics justify it.

Why does Google Ads CPA differ from my backend?

Attribution windows, cross-device behavior, consent, conversion definitions and reporting dates can create differences.