Analytics

Ad Impressions

The number of times an advertisement is displayed, regardless of whether it was clicked.

Definition

An impression is counted each time an ad is served and displayed on a screen. Impressions measure raw exposure — how many times your ad appeared in front of potential viewers. One user can generate multiple impressions if they see your ad more than once (see: Frequency). Impressions are the foundational unit of measurement in display advertising and are the basis for CPM pricing. It's important to distinguish between served impressions (the ad was technically delivered) and viewable impressions (the ad was actually on-screen).

Key Points

  • One user can generate many impressions — impressions ≠ unique viewers
  • Impressions are a supply metric; they measure potential reach, not guaranteed views
  • Used as the denominator in CPM, CTR, and eCPM calculations
  • Unique impressions deduplicate by user; total impressions do not

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