The Google Tag (gtag.js) Explained: G-, AW- & GT- IDs

The Google tag (gtag.js) is Google’s unified tag for sending data to multiple Google products, GA4, Google Ads and more, from a single snippet.

G-, AW- and GT- IDs

• G-XXXX, a GA4 property
• AW-XXXX, a Google Ads account
• GT-XXXX, a Google tag “destination” that can fan out to several IDs

One Google tag can feed several destinations, which is why you may see it paired with both analytics and ads.

Where you’ll see it

It appears either hard-coded in the page <head> or as a Google Tag inside a GTM container. Tag Explorer shows both, with the ID as the title.

Why it matters

The Google tag is the modern foundation for Google measurement. Duplicate Google tags (e.g. one hard-coded and one in GTM with the same ID) double-count and should be consolidated.

How to check yours is working

Run your site through our free Tag Explorer tool, it shows every tag on the page, nested under its GTM container, with the tracking IDs. To confirm a tag actually fires, use GTM’s Preview mode or your browser’s DevTools Network tab.

---

Part of the Shipwreck Studio Tag Guide. Scan any page with Tag Explorer to see its full tag tree and spot duplicates.