CPM (Cost Per Mille)

Cost Per Mille (mille = thousand) pays based on impressions rather than clicks or conversions — the publisher earns a set rate for every 1,000 times an ad is shown. It is the standard pricing unit for display and programmatic advertising.

CPM prices advertising by exposure rather than response: the affiliate or publisher is paid a set rate for every thousand times an ad is displayed. 'Mille' is Latin for thousand, and the metric exists so brands can buy reach at a comparable unit cost across placements. Payment depends only on impressions served, not on clicks or sales, which makes it the purest awareness-driven model.

Advertisers reach for CPM when the goal is visibility — brand launches, reach campaigns, or topping up the awareness stage of a funnel — where being seen matters more than an immediate action. Publishers with heavy traffic like CPM because inventory earns whether or not readers engage, giving predictable revenue per page view once fill rates are known.

The weaknesses are viewability and fraud. An 'impression' can be counted even if the ad loads below the fold and is never actually seen, so the industry layered on viewable-impression standards, but discrepancies persist. Impression fraud through bot-loaded pages also inflates counts, and effective CPM (eCPM) is often used to compare real yield across formats after these losses.

Programmatic buying and real-time bidding turned CPM into the base currency of display and video advertising, with dynamic pricing set at auction. The rise of viewability guarantees and attention metrics reflects advertisers pushing back against paying for impressions that deliver no genuine exposure.