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CAC vs CPC: what ecommerce marketers should compare

2026-05-19 16:14 · Paid Marketing

CAC and CPC measure different parts of the funnel. This guide explains when ecommerce marketers should use each metric.

CAC and CPC both describe marketing cost, but they sit at different points in the funnel.

CPC means cost per click. It tells you how much you paid for each click from an ad or campaign. It is useful when comparing traffic cost across channels, keywords, audiences, or ad creatives.

CAC means customer acquisition cost. It tells you how much you paid to acquire one new customer. It is useful when judging whether marketing spend can produce customers at a sustainable cost.

A low CPC does not always mean a good campaign. If clicks are cheap but few visitors buy, CAC can still be too high. A higher CPC can still work if the visitors convert well and the resulting CAC fits your margin or customer lifetime value.

Ecommerce marketers should usually look at both. Use the CPC Calculator to understand traffic cost, then use the CAC Calculator at /tools/cac-calculator to understand the cost of actual new customers. ROAS and ROI add another layer by showing revenue and return.