A new user, in Google Analytics 4, is someone recorded as visiting your website or opening your app for the first time. In practice GA4 means a browser or device it has not seen before, which is not always the same as a person who has never heard of you.
How new users are counted
When a visitor arrives and GA4 finds no existing analytics cookie, it creates a new client ID, stores it in a first-party cookie and sends a first_visit event (first_open in apps). The New users metric counts those events. Anyone arriving with an existing cookie, from an earlier visit in the same browser, counts as a returning user instead.
Because the cookie is the memory, anything that removes or bypasses it makes a returning person look new:
- Visiting on a different device, such as browsing on a phone at lunchtime and coming back on a laptop in the evening.
- Using a different browser or a private window.
- Clearing cookies, or a browser clearing them automatically. Safari’s Intelligent Tracking Prevention limits how long some cookies last, so a Safari visitor returning after a week or so may be counted as new.
If you send your own login or customer ID as a user ID, GA4 can recognise signed-in people across devices, which reduces this inflation for those users.
GA4 also records where each new user first came from. The first user default channel group and related “first user” dimensions keep that original source, which is what the User acquisition report is built on.
Why it matters
New users is one of the clearest signals of reach. If a UK business is investing in SEO, local search or brand campaigns, a steady rise in new users from those channels suggests more people are discovering it. The ratio of new to returning users also hints at loyalty: a café booking site or a subscription shop wants plenty of returning visitors, while a one-off service such as conveyancing will mostly see new ones.
The cookie consent picture changes what you see in the UK. Visitors who decline analytics cookies cannot be given a lasting client ID, so they are either absent from reports or estimated through modelling. Your new user figure therefore reflects consenting visitors, plus any modelled estimate, rather than every person who arrived.
Common mistakes
- Reading New users as a count of new customers or new people. It counts new browser and device combinations.
- Celebrating a jump in new users after a site change, when the real cause is a tracking fault creating fresh client IDs on every page.
- Comparing GA4 new users with Universal Analytics figures from years ago, which used different definitions.
- Ignoring the difference between first user and session dimensions, then wondering why channel totals differ between reports.
- Setting a target on new users alone, which rewards cheap, unqualified traffic.
How to act on it
- Use the User acquisition report to see which channels bring new users, and the Traffic acquisition report for sessions from all users.
- Pair new users with a quality signal, such as engaged sessions or key events per new user, so you are judging useful reach rather than raw volume.
- If new users suddenly rise while returning users fall, check whether your analytics cookie is being reset, for example by a consent tool or a cross-domain checkout.
- Where customers log in, consider sending a user ID so the same person is recognised across devices.
Reading acquisition reports correctly is part of the measurement groundwork in my performance marketing work, so that growth in reach is real growth and not an artefact of how users are counted.