How-to · Updated October 11, 2026
Check whether a tracking tag is really on your website
Updated October 11, 2026
15 minutes
Don't judge by page source. Tags added in Tag Manager are loaded by its script after the page arrives, so they never appear in the source the server sends, and a tool reading only that source calls them missing. Check the live site with Tag Assistant or Chrome's Network tab, then the container's published version.
Before you start
- Google Chrome, for Tag Assistant and Developer Tools.
- The tag's ID or address, such as a G-, AW- or GTM- ID, or the script address a call tracking or ad platform gave you.
- Read access to the Tag Manager container, if the site uses one.
Know what page source can show
Page source shows the HTML the server sent, which holds only the tags written straight into the page.
- Open the page in Chrome, right-click and choose View page source, then search for the ID. A tag written into the page, such as the Google tag's gtag/js?id= line, shows here.
- Search for GTM- as well. If the Tag Manager snippet is there, every tag added inside the container is loaded by that snippet in the visitor's browser and will not appear in the source. The answer for those is in the container, not the HTML.
- Treat a scanner or audit that fetches the page without running it the same way: it can report a Tag Manager tag as missing while the tag works.
Check the live page in a real browser
A real browser runs Tag Manager and every script it loads, so it shows what visitors actually get.
- Go to tagassistant.google.com, click Add domain, enter your website address and click Connect. Read the tags under the Google tags found header: your ID should be there, with a green or blue status icon.
- For any tag, Google or not, open Chrome's Developer Tools (the three-dot menu, More Tools, Developer Tools, or F12 on Windows, Cmd+Option+I on a Mac), select the Network tab and reload the page. Type the ID or part of the script's address into the filter box: a request means the tag loaded on this page. For Google tags, also filter for googleadservices.com (Google Ads) or analytics.google.com (Analytics), the addresses Google says to check. An empty result for the ID alone does not prove the tag is missing.
- Turn off ad blockers for the site, accept its cookie banner and test again. Google notes that consent tools and ad blockers can stop tags from running, so a test in a browser with an ad blocker, or before consent, can show a working tag as absent.
- Repeat on the pages that matter: the landing pages your ads send people to and the page shown after a form is sent. Google says a sitewide tag is needed on all pages to store the ad click.
Confirm the tag in the container's live version
If the site uses Tag Manager, the published version of the container is the record of what visitors run.
- In Tag Manager, click Versions and look for the versions with a date in the Published column. The newest of them is normally the one live on the site.
- Find the tag and its trigger. A tag sitting in a workspace but not in the published version is not on the site.
- Check that the GTM- ID Tag Assistant found on the site is the container you are reading. A site can load a different container, or two.
Check it worked
You should be able to name, for each tag in question, the page you tested, the request or Tag Assistant entry that proves it loaded, and the place it is set up: the page's code or the container's published version.
If you fixed a Google Ads conversion tag, Google says to allow 24 to 48 hours for its tracking status to update.
When the tag loads late
Some sites delay Tag Manager until the visitor scrolls or clicks, to speed up the first load. On those sites, a quick look after the page appears can miss everything. Scroll and click before reading Tag Assistant or the Network tab. Google notes the tag script can load after Tag Assistant tries to connect; if it does not connect, click Retry.
When the tag is there twice
Google advises using either the Google tag snippet or Tag Manager, not both, since using both can overcount, and against multiple Google tags or containers on one page. If Tag Assistant flags a duplicate, or the Network tab shows the same ID loading twice, find the second copy before anything else.