free tool

Is Google Tag Manager installed on this site?

Paste any URL. We read the page source and tell you whether Tag Manager is there, plus the container ID if we find one.

Free, no signup. We read only public page content.

free tool

How to know if a website uses GTM (Google Tag Manager)

Open the page's source (Ctrl+U, or Cmd+Option+U on a Mac) and search for GTM- or gtm.js. If Google Tag Manager is installed you'll find a container ID like GTM-ABC1234. Don't want to dig through code? Paste the URL above.

1

Read the page source

Right-click the page and pick “View page source”, or press Ctrl+U. Use the find box to look for GTM-. A match means a container is loaded on that page.

2

Check the Network tab

Open DevTools (F12), go to Network, type gtm.js in the filter, then reload. A request to googletagmanager.com with an id=GTM-… parameter confirms it, even if the snippet is added by JavaScript.

3

Use Google Tag Assistant

Google's own Tag Assistant connects to a site and lists every tag firing, including the GTM container and anything inside it. Useful when you want to see what the container actually does, not just that it exists.

4

Paste it above

The fastest option when you just need a yes or no and the container ID. No extension, no DevTools, works on any URL.

questions

Google Tag Manager, answered.

It's the letters GTM- followed by six or seven letters and numbers, like GTM-ABC1234. One site can run more than one container, so it's normal to find a few.
No. Tag Manager is a container that loads other tags for you. Google Analytics (the G-XXXX measurement ID) is one of the tags people commonly load through it. A site can run Analytics with or without Tag Manager, so finding one doesn't guarantee the other. Check a site for Google Analytics →
A few reasons. Some sites hold the tag back until a visitor accepts cookies, some load it through a consent platform, and some add it server-side or with JavaScript after the page opens. We read the HTML the server first returns, so anything injected later won't always appear. The Network tab or Tag Assistant will catch those cases.
Yes. The install snippet sits in public page source, so anyone viewing the page can see whether a container is present and what its ID is. You can't see inside their container or their data, only that it's there.
No. The ID only names the container. The account and everything configured in it stays private to whoever owns it.
The check is free and reads only public page source. We don't save the URLs you enter. Tag Manager itself is also free from Google.