Cost per action (CPA)(CPA)

MetricsCross-platform

Cost per action (often used interchangeably with cost per acquisition) is spend divided by counted conversions: CPA = spend ÷ conversions. It is the primary efficiency metric for lead-gen and purchase campaigns when the conversion event is well-defined and stable.

Define the conversion event explicitly (purchase vs. lead vs. signup) before comparing CPA across campaigns.

Sources

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Last verified Jun 3, 2026

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