Cost per click (CPC)
What you actually pay each time somebody clicks your ad: total spend divided by clicks.
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What it is
CPC is what you actually paid for a click: total spend divided by clicks. Your bid is the ceiling you are willing to pay and the auction decides the rest, so you usually pay less than the full bid. How much less is platform business: each one runs its own auction with its own quality scoring, eligibility thresholds, context signals, and pricing rules, and none of them hand you a formula you can carry from Google to Meta to Amazon.
Two things move it. Competition, which is why a click on 'mesothelioma lawyer' can run into three figures while a niche B2B tool costs 80 cents, and relevance, which platforms score (Google calls it Quality Score) and reward with cheaper clicks for ads and landing pages that match the query. Improving the landing page is a bidding strategy, oddly enough.
Gotcha: cheap clicks are not the win condition. CPC is an input to the number that matters (what a customer costs you), so a $4 click that converts at 8% beats a $0.40 click that converts at 0.1%. Broad targeting and low-quality placements are the usual way people accidentally buy a beautiful CPC and no revenue.
Ask AI for it
Build a CPC breakdown view for a paid search dashboard. Show a horizontal bar chart of the top 10 keywords or campaigns sorted by spend, using spend as the bar length. Never split one bar between clicks and money, since the units do not mix: print clicks, average CPC as currency, and conversion rate as a percent beside each bar, or draw a second aligned click bar under the spend bar with its own scale. Add a scatter plot underneath with CPC on the x axis and cost per conversion on the y axis, one dot per keyword sized by spend, plus a target line so overpriced keywords sit visibly above it. Currency formatted to two decimals, muted grid, one accent color.