Marketing
Cost Per Acquisition Calculator
Calculate the average cost per acquisition from campaign spend and the acquisitions it produced.
Enter total campaign spend and the number of acquisitions in the same period.
Enter your values
Spend for the campaign over the measurement period.
Conversion events credited to the same campaign and period.
Results
Cost per acquisition
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Enter campaign spend and acquisitions.
Total campaign spend
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The spend figure entered.
Acquisitions
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The acquisitions entered.
Results are estimates based on the values entered and are provided for general planning.
Method
How to calculate CPA
CPA divides what a campaign cost by how many acquisitions it delivered, giving the average price paid for each one. Because it is an average, it flattens variation between channels, audiences, and creatives inside the same campaign.
Formula
CPA = Total campaign spend ÷ Acquisitions
Assumptions
- Spend and acquisitions cover the same campaign and the same time period.
- An acquisition is whatever conversion event your business is counting.
- Acquisitions is a positive whole number, because dividing by zero acquisitions has no defined cost.
- Only the spend entered is included — creative, agency, and tooling costs are excluded unless you add them.
The division is calculated at full precision before display. Currency displays two decimals; acquisitions display as whole numbers.
How to interpret the result
CPA tells you the average price of a conversion under the spend you entered. It does not tell you whether that price is affordable — that depends on what an acquisition is worth to you. Compare CPA against the revenue or margin a converted customer generates before drawing conclusions.
CPA vs CAC
The two metrics are often used interchangeably, and often incorrectly. CPA typically answers 'what did this campaign pay for each conversion event?' CAC typically answers 'what did the business pay, across all acquisition activity, for each new paying customer?'
The gap between them matters. A campaign can report a $25 CPA on free-trial signups while the business CAC per paying customer is several times higher, because only a fraction of trials convert and CAC also carries salaries, tooling, and channels the campaign never touched.
What moves CPA
CPA is the product of two things: how much traffic costs and how well that traffic converts. It can fall because clicks got cheaper or because the landing page converted better — the number alone does not tell you which.
Separating CPC from conversion rate is usually more actionable than watching CPA move on its own.
Frequently asked questions
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