In Google Analytics 4, a 'user' is an individual who visits your website, identified by a unique GA4 identifier (a cookie or device ID). A 'session' is a single continuous visit to your website — one user can have multiple sessions if they visit more than once. The ratio of sessions to users tells you how often, on average, users return: a ratio of 1.2 means most users visit only once; a ratio of 2.0 means on average each user visits twice. GA4 also distinguishes between 'total users' (everyone who visited in the period) and 'new users' (those who had not been to the site before in the same period).
Understanding the sessions/users distinction is important for interpreting traffic reports correctly. If your website had 10,000 sessions and 8,000 users last month, it means 8,000 individuals visited, and some visited more than once (accounting for the extra 2,000 sessions). For e-commerce or high-consideration services, a high sessions-to-users ratio is positive — it suggests visitors are returning to research before purchasing. For simple lead generation sites, a single session is often sufficient for conversion, and a high ratio might suggest visitors are struggling to find what they need.
Key user and session metrics in GA4
- Total users — all individuals who visited in the selected period, including returning visitors
- New users — individuals visiting for the first time; a high proportion of new users indicates strong acquisition; a low proportion suggests strong retention
- Returning users — individuals who have visited previously; important for brand loyalty and email/content marketing assessment
- Sessions — total visits in the period; more sessions than users means some visitors returned multiple times
- Sessions per user — average number of times each user visited; benchmarks vary, but 1.2–1.5 is typical for most UK websites
- Engaged sessions — GA4's replacement for the bounce metric; sessions lasting 10+ seconds, with 2+ page views, or with a conversion event
- Engagement rate — percentage of sessions that were 'engaged'; 40–60% is typical; below 30% suggests poor traffic quality or poor landing experience
Several factors can cause apparent inconsistencies between user and session counts: (1) Cross-device tracking — the same person visiting on mobile then desktop may be counted as two users unless they are signed into a Google account. (2) Cookie deletion — if a returning visitor deletes cookies, they are counted as a new user. (3) Data sampling — in reports covering large datasets, GA4 may sample data, introducing slight inaccuracies. (4) Bot traffic — automated bots can inflate both session and user counts if not filtered. These are not errors but limitations of cookie-based analytics measurement, which GA4 partially addresses through machine learning modelling.
It depends on what you're measuring. For understanding audience reach (how many individual people saw your content), total users is the right metric. For understanding visit volume and return behaviour (how frequently your audience engages with your site), sessions is more useful. For campaign performance measurement, sessions per campaign source shows how much traffic each channel generates. For content performance, engaged sessions per page shows which content generates genuine interaction. Many analysts now also focus heavily on 'engaged sessions' as the primary quality indicator, replacing the old bounce rate focus.