What is CPC in advertising?

CPC is spend ÷ clicks. If an ad cost $90 and Meta’s report shows 300 clicks, the CPC is $0.30. The same ad had 30,000 impressions, so its CPM was $3 and its click-through rate was 1%. Those three numbers always agree: CPC equals CPM divided by the number of clicks per 1,000 impressions.

• At 30 clicks per 1,000 impressions and a $3 CPM, a click costs $0.10.
• At 10 clicks per 1,000 impressions and the same $3 CPM, a click costs $0.30.
• At 5 clicks per 1,000 impressions, it costs $0.60.

So CPC falls when more people click, even though you pay the same for the impressions. That is why improving the creative can lower CPC without touching the bid.

Meta’s reference lists several click-cost fields, not one. Plain cpc is the average cost per click (all). Others cover cost per inline link click, cost per unique click and cost per outbound click. The names suggest the narrower versions count only certain click types. Check how your own report defines the one you are looking at.

This matters because “all” clicks may include actions that are not a visit to your website, such as expanding a caption or interacting with the post. Check your own report’s definition. If your goal is traffic, the link-click versions are the closer match, and reading all-click CPC as cost per visitor can understate your real cost.

A cheap click is not a good click. A $0.10 click from someone who leaves at once costs more per sale than a $1 click from someone who buys. Pair CPC with the conversion rate: if 2 in 100 clicks become customers, a $0.30 CPC means each customer costs about $15 in clicks.

Tip: Do not chase the lowest CPC. Set a target cost per result first, then work backwards: cost per result ÷ the number of clicks needed per result gives the CPC you can afford.