What is CPC?

CPC — cost per click — is what one click costs on average: spend divided by clicks. It prices the traffic a channel sends you, whatever that traffic later does.

Formula

CPC = ad spend ÷ clicks

Worked example

A channel spends €6,000 in the selected period and reports 12,000 clicks: CPC is €0.50. Another spends €6,000 for 4,000 clicks: €1.50. Whether the €1.50 channel is worse depends entirely on what a click is worth there — if its visitors convert at three times the rate, the two channels pay the same per conversion.

How Saldo Metrics computes it

v_channel_performance computes cpc_base per channel per day as summed spend_base over summed clicks; the channel summary on Marketing → Overview recomputes the same division across the selected period's daily rows, and v_channel_summary carries the lifetime figure (avg_cpc_base). The spend side is EUR, converted from each day's as-billed amount at that day's ECB rate before summing, so a period CPC never mixes currencies. Days with spend but zero clicks still contribute their spend — CPC is total over total, not an average of daily CPCs.

Why it matters

CPC connects the auction to your economics: it is the bridge between what attention costs (CPM, CTR) and what a visit may return (conversion rate, margin). Rising CPC at stable CTR means the auction itself got more expensive; rising CPC at falling CTR means your creative is losing the auction's quality discount — two different problems with the same symptom.

Common mistakes

• Judging channels on CPC alone. A cheap click that never converts is worth less than an expensive one that does. Price traffic against the margin it produces.
• Comparing CPC across channels with different click definitions. A platform counting every engagement shows a flattering CPC next to one counting link clicks only.
• Averaging daily CPCs. Low-volume days would count as much as high-volume ones; the correct period figure is total spend over total clicks.

Where you see this in the app

Marketing → Overview, in the channel summary table's CPC column.