The first_visit event and new users
The first_visit event is fired the first time a user opens your site in a browser. It is how GA4 distinguishes new users from returning ones: the presence of a first_visit defines a new user. Because it depends on a stored marker, clearing cookies or using a fresh browser makes the same person look new — a limitation worth understanding before trusting new-user counts.
What this means
GA4 fires first_visit automatically the first time a user visits with analytics and storage available. It establishes the user as new; subsequent visits with the same marker are returning. The new_vs_returning dimension and most acquisition reports lean on this event.
Why new users can be overstated
first_visit depends on a stored identifier. Clear cookies, open a private window, switch devices, or block storage, and the same person triggers first_visit again — counted as a brand-new user. So a rising new-user share can be growth, or it can be churn of the marker. Treat new-versus-returning as directional, not exact.
- Fires once per browser/storage marker
- Defines the user as new for reporting
- Cleared or blocked storage re-counts the same person
How it appears in analytics and logs
A first_visit means a browser had no prior marker. A high new-user share can be real growth or just visitors who block or clear storage, so confirm before celebrating.
Diagnostic use case
Read the new-versus-returning split correctly by knowing first_visit fires once per browser marker, and that storage resets inflate new users.
What WebmasterID can help detect
WebmasterID derives new-versus-returning from first-party signals only, so the split reflects your own site without third-party cookies or cross-site identity.
Common mistakes
- Treating new users as a precise count of distinct people.
- Ignoring storage clearing and private browsing inflation.
- Comparing new-user share across tools with different markers.
Privacy and accuracy notes
first_visit relies on a first-party marker, not a cross-site profile. New-versus-returning is a coarse, local distinction and does not require tracking a person across other sites.
Related pages
- The session_start event
The session_start event marks the beginning of a visit. In GA4 it is fired automatically the first time a user is active in a new session, and it underpins every session-scoped metric. Understanding when a session begins — and the timeout that ends it — explains why session counts behave the way they do across midnight, campaigns, and idle periods.
- User properties vs event parameters
User properties are attributes that describe a user across all their events — a plan tier, a preferred language, a logged-in state — rather than a single action. They differ from event parameters, which describe one event. Used well, user properties let you segment behaviour by audience. Used badly, they become a place where people stash personal data, which is exactly what they must not hold.
- Cookieless analytics: how it works and its limits
Cookieless analytics records visits and events without setting cookies or persistent cross-site identifiers. It relies on first-party, server-side signals and aggregate counting. The trade-off is honest: it cannot follow an individual across sessions the way cookie-based tracking can — which is exactly the point for privacy-first measurement.
- Web analytics
New-vs-returning from first-party signals.
Sources and verification notes
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.