CPC is ad spend divided by clicks — the price of traffic. It's an input cost, not a success metric: cheap clicks that don't convert are expensive.
Definition
CPC = spend ÷ clicks. In auction platforms it's set dynamically by competition, quality signals, and bidding strategy rather than by a fixed rate card. CPC matters as a diagnostic — rising CPCs signal heavier competition, weakening ad relevance, or auction changes — but optimizing to CPC directly optimizes for cheap traffic, which is rarely the goal.
Why it matters
CPC explains where efficiency changes come from. When CPA rises, decomposing it (CPA = CPC ÷ conversion rate) tells you whether the problem is pricier traffic or a worse-converting funnel — two problems with completely different fixes.
In agentic execution
Adlyse's agents use metrics like CPC diagnostically — as signals in the loop that decides what to change — while executing toward the conversion and value targets the team actually cares about.
Related terms
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