How Users is measured
A Session is a single visit. Users counts the distinct people behind those visits, identified by an id the tracking snippet stores in the visitor's own browser, in localStorage and a first-party cookie that lasts 365 days. Two visits carrying the same id are one person.
That id is created in the browser and never leaves it in a form that identifies anyone. It tells us that two visits belong to the same person; it does not tell us who that person is.
What changed in July 2026
Until July 2026 the Users metric was built on a session-level identifier created on our servers rather than on the visitor's stored id. It did not reliably survive between visits, so one returning person could be counted as several. We corrected it to use the browser-stored id.
Users may be slightly lower
For most properties the reported number falls by under 3%. It was never that the visits went missing, only that one person had been counted more than once.
Loyalty metrics get more accurate
Returning visitor rate, sessions per user and retention were all understated, because a returning person often looked like a new one. Those numbers generally rise.
Nothing else moves
Sessions, pageviews, events and conversions are counted independently of visitor identity and are unchanged.
The size of the correction depends on how often your visitors come back, not on how much traffic you have. A site whose visitors mostly arrive once and leave will barely move. A site with a small, loyal audience can change a great deal, because those repeat visits were previously being counted as separate people. Because these numbers are calculated when a report is opened, past date ranges reflect the corrected method too.
If you forward events to Google Analytics 4, the same correction applies there: datataste previously flagged a returning visitor as a first-time visit when their session storage had lapsed, so GA4's New Users was inflated in the same way. That number will step down too, and for a site with a loyal audience the step can be large.
The limitation that remains
The visitor id lives in browser storage, and Safari and iOS limit how long a site may keep it to seven days. Someone returning after longer than that arrives without it and is counted as a new user.
This affects every analytics tool that measures users this way, including Google Analytics 4, and it is a consequence of respecting the browser's privacy rules rather than working around them. Sessions, pageviews, events and conversions are not affected by it.