Impression
An impression is a metric in digital advertising that means the display of an advertisement to a user on a screen.
Simply put:
every time an ad appears and loads — that counts as an impression
How an Impression Is Counted
An impression is recorded when:
- an ad banner loads on a page;
- a video ad starts playing;
- an ad appears in an app or on a website.
Important: no click is needed — the mere fact of display is enough.
Types of Impressions
- Served Impression
The ad was simply loaded on the page (not necessarily visible to the user). - Viewable Impression
The ad actually entered the user’s viewable area (e.g., 50% of the banner visible for at least 1 second).
Example
If:
- 1,000 users opened a page with an ad;
- the banner loaded for all of them;
that = 1,000 impressions
If only 600 of them actually saw the ad on screen:
that = 600 viewable impressions
Why Impressions Are Needed
Impressions are used for:
- measuring ad reach;
- calculating CPM / vCPM;
- brand awareness analysis;
- planning advertising campaigns;
- comparing channel effectiveness.
Related Metrics
- CTR (Click-Through Rate) — clicks / impressions
- CPM — cost per 1,000 impressions
- vCPM — cost per 1,000 viewable impressions
- Reach — unique users
Important to Understand
- 1 user can generate many impressions,
- impressions ≠ clicks,
- impressions ≠ actual views (if not viewable).
Key Takeaways
An impression is the fact that an advertisement is displayed to a user on a screen.
This metric is used to measure reach and is a fundamental unit in digital advertising.
