Building audiences

An audience (Admin > Audiences) is a saved user-group definition that GA4 evaluates continuously: as users meet the conditions they join, and after the membership duration (default 30 days, max 540, or no limit) without re-qualifying they drop out. Unlike a segment, an audience is not retroactive: it fills from creation onward, and the initial population only includes users who match in the next 30 days of activity. Create audiences early.

The builder is the same as the segment builder: include and exclude condition groups, scoping (across all sessions / within the same session / within the same event), and sequences. You can start from suggested audiences (purchasers, recently active, by template) or from a user segment in Explore with Build an audience ticked. Up to 100 audiences per property (400 for 360); archived ones do not count.

Where audiences show up:

• as a dimension Audience name in reports and Explore, and as a comparison condition,
• in the Audiences report under User attributes with users, sessions and revenue per audience,
• in Google Ads (if linked with personalised advertising on) for remarketing, observation and exclusion lists; in Display & Video 360 and Search Ads 360 via their links,
• in Firebase for app messaging and remote config.

Audience triggers: in the audience editor, Create new under Audience trigger names an event that GA4 fires when a user joins (optionally every time they re-qualify). Mark that event as a key event and you have turned a behavioural pattern, like "viewed three product pages and spent five minutes", into a conversion that Google Ads can bid on. Triggered events cost nothing and do not need code.

Audiences built on Google signals (demographics, interests) are usable for remarketing only when signals is on; such audiences also make thresholding more likely.