Sessions

Sessions are periods of activity during which a single user interacts with your site, grouping that user's events and page views into one visit. A session begins when a user arrives and engages, and it ends after a stretch of inactivity, which lets analytics count visits rather than treating every page view as a separate, disconnected event.

The exact mechanics depend on the tool. In Google Analytics 4 a session is started by a session_start event and is held open by ongoing activity; by default it times out after 30 minutes of inactivity, and the next engagement after that gap begins a new session. GA4 also changed an older convention: it no longer automatically splits a session at midnight or when a new campaign source appears mid-visit, which means GA4 session counts can differ from what Universal Analytics would have reported for the same behavior.

Sessions sit between users and events as a unit of measurement. One user can have many sessions over time, and each session can contain many events, so the same activity can be described at three levels. Choosing the right level matters: users tell you reach, sessions tell you how often people come, and events tell you what they do. Metrics like engaged sessions and average engagement time refine the picture by separating genuine visits from quick bounces.

A few caveats keep session counts honest. Timeouts, multiple devices, and privacy controls that limit tracking can all inflate or fragment the count, since a person who steps away and returns, or who switches phone to laptop, may register as more than one session or user. Reading sessions alongside users and engagement metrics, rather than in isolation, gives a truer sense of how people actually use the site.

Related: Organic Traffic, Landing Page Report, Segments