CAC vs CPA: What's the Difference?

CAC and CPA can look similar because both divide cost by outcomes, but they often answer different business questions.

CPA

Cost per acquisition or action usually refers to spend divided by a defined conversion such as a lead, signup or purchase. The exact “A” must be stated clearly.

CAC

Customer acquisition cost typically focuses on the cost to acquire a new customer and may include more than direct ad spend, such as sales or marketing costs depending on the organization’s definition.

Why the distinction matters

A campaign can have a low lead CPA but a high customer CAC if lead quality is weak. Optimizing only the earlier metric can hide a downstream business problem.

Use consistent definitions

Document which costs and outcomes are included. Metric names are less important than maintaining a definition that remains stable across time and teams.