CPM (cost per mille)
CPM is the price paid for every thousand impressions of an ad. It is the most common buying unit in display, video, connected TV and digital out-of-home.
It is calculated by dividing the campaign cost by the impressions served and multiplying by a thousand: €5,000 for one million impressions is a €5 CPM. It coexists with other models such as cost per click (CPC), per completed view (CPCV) or per action (CPA), depending on what the campaign wants to pay for.
CPM on its own says little: a low CPM can hide impressions that nobody sees or that reach the wrong people. That is why it is compared with quality metrics (viewability, completion rate, reach within the target audience) and what really counts is the cost per relevant person reached, not per impression.
