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GA4 tag checker

Last updated October 31, 2026

Enter a website address to check whether it loads a Google Analytics 4 tag, which measurement IDs (starting with G-) it uses, and whether Google Tag Manager or a consent manager is present. The checker reads the page the way a browser receives it, the script files the site serves itself, and any Tag Manager container the page loads. It doesn't run scripts, so a tag added only after a visitor accepts cookies or interacts may not show.

Free, no sign-up. We fetch the page once and don't store the address or the result.

Check by hand in four steps

  1. 1

    Search the page source

    Open the page, view its source and search for G- and GTM-. A GA4 measurement ID looks like G- followed by letters and digits; a Tag Manager container looks like GTM- followed by letters and digits.

  2. 2

    Use Tag Assistant

    Google's Tag Assistant (tagassistant.google.com) connects to the page and lists every Google tag that fires, with its ID.

  3. 3

    Watch the Realtime report

    Open the property in GA4, go to Reports, then Realtime, and visit the site. If you appear within a minute, data is arriving.

  4. 4

    Confirm events in DebugView

    Turn on debug mode with Tag Assistant and open Admin, then DebugView, to see each event as it arrives, on every page you test.

How to read the result

  • GA4 tag found: the site loads a GA4 tag. The result says whether the ID is in the page, in a script file the site serves, or inside a Tag Manager container.
  • Tag Manager found, but no GA4 ID: the page loads a container, but no GA4 ID appears in it or in the page. GA4 may be loaded another way, or not set up at all.
  • Only Universal Analytics: the site still has an old UA- tag. Universal Analytics stopped processing data in 2023, so the site needs a GA4 tag.
  • Nothing found: no Google tag in the page or the site's own scripts. Either the tag is missing, or a third-party script adds it later.

A tag is there, but GA4 shows nothing

  • The measurement ID belongs to a different property. Compare it with the web stream in Admin, Data streams.
  • A consent setup blocks Analytics until visitors accept. See why GA4 data dropped after a cookie banner.
  • A data filter excludes real traffic, or today's reports are still processing.
  • Work through the full checklist in GA4 not showing data.

What the checker can't see

  • Tags added by JavaScript after the page loads from another domain, after consent, or after a click.
  • Server-side tagging that loads Tag Manager from your own domain under a different path.
  • Pages behind a login, and sites that block automated requests (they usually answer with an error).
  • Whether data actually reaches GA4. Only the Realtime report or DebugView proves that.

Privacy

The checker is free and needs no account. It fetches the page you enter once, from SilenceRadar's servers, identifying itself as SilenceRadar-TagCheck. The address and the result are not stored. Each person can run 10 checks a minute.

A tag check is a snapshot. To hear about it when a tag disappears later, silence alerts watch every connected GA4 property every 15 minutes.

Questions

How do I check if Google Analytics is installed on a website?

Enter the address in the checker above, or view the page source and search for G- (GA4) and GTM- (Tag Manager). To confirm data arrives, visit the site with the GA4 Realtime report open.

What does a GA4 measurement ID look like?

G- followed by a string of letters and digits, for example G-AB12CD34EF. You can find yours in GA4 under Admin, Data streams, on the web stream.

Why does it find Tag Manager but no GA4 ID?

GA4 may be added another way, through server-side tagging, or not at all. Open the Tag Manager container to check for a Google tag that fires on all pages, and make sure the latest version is published.

Can I check any website?

Any public page. The result shows which Google tags the page loads; it doesn't give access to anyone's analytics data.

Is the checker free?

Yes. There is no sign-up, and nothing you enter is stored.