Updated: December 18, 2025
New Users
In GA4, New Users are determined by the first_visit (web) or first_open (app) events.
first_visit is automatically fired when GA4 detects a new Client ID, in the GA4 first request, _fv stands for first_visit.
Important note: If the first_visit or first_open events are missing, the number of new users will be undercounted.
Example: If a new visitor interacts with your site but no first_visit event is triggered, GA4 will not count them as a New User.
Returning Users
Returning Users are users who have previously visited your website or app and come back during the reporting period. In GA4, these are users with session count > 1.
Example: A visitor comes back after a previous visit—they are counted as a Returning User.
The session count (sct) is stored in the cookie _ga_<container-id>：
Every request sent to GA4 includes the sct parameter：
Further reading:
New Users vs Returning Users
| Metric | Count Basis | Where from |
|---|---|---|
| New Users | first_visit/first_open | GA4 automatically fired |
| Returning Users | session count>1 | cookie _ga_<container-id> |
The two are calculated completely independently, A single user may appear in both New Users and Returning Users if reporting spans multiple sessions across days.
For example：if a person visits for the first time in the morning and visits again in the afternoon (the interval is more than 30 minutes), then on this day, New Users is 1, Returning Users is 1.
Read More：New Users vs Returning Users vs Users vs Total Users in GA4
