Paid ads

CPC or CPM: which lever you are actually pulling

CPC is what you pay for a click. Use it when the job is traffic you can send to a page that converts.

CPM is what you pay for a thousand impressions. Use it when the job is reach or a view - brand, video, frequency - not a click you intend to monetise today.

Comparing a search CPC to a display CPM in one sentence is how teams argue past each other. Name the unit, then the outcome (CPA or ROAS).

If you only have spend and clicks, start with CPC. If you have spend and conversions, add CPA. If you have revenue, add ROAS. Do not skip to ROAS from impressions alone.