Skip to content
Tag Manager Training
GTM & GA4 glossary

Google Ads · GTM glossary

GCLID

A unique ID that Google Ads adds to your landing page URL when someone clicks an ad. It lets a later conversion be traced back to that exact click, campaign and keyword.

Also known as: Google Click Identifier, Google Click ID, gclid, Auto-tagging

On this page
  1. In plain English
  2. Example
  3. Official documentation
  4. Related terms

In plain English

When auto-tagging is switched on in Google Ads, every ad click lands on a URL like example.com/?gclid=Cj0KCQ…. That value identifies the click, and Google Ads uses it to work out which campaign, ad group and keyword a conversion came from.

The GCLID only appears in the landing page URL, so something needs to save it. The Conversion Linker tag in GTM (or the Google tag) stores it in a first-party cookie, so a conversion several pages or days later can still be credited to the click.

Auto-tagging is on by default in new Google Ads accounts. If GCLIDs are missing, check it hasn't been switched off, and that redirects or the website itself aren't stripping URL parameters.

For some clicks from Apple iOS devices, Google Ads adds gbraid or wbraid instead. They do a similar job in a more privacy-friendly way.

Example

A plumbing business gets enquiries through its website form, but only some become paid jobs. A hidden form field captures the GCLID, so each enquiry in the CRM records which ad click it came from. Completed jobs are then uploaded to Google Ads as offline conversions, so Smart Bidding optimises for paying jobs rather than form fills.

Official documentation

Last reviewed

Next step

Want your team to know this without looking it up?

Hands-on Google Tag Manager and GA4 training for agencies and marketing teams in Brisbane, the Gold Coast and the Sunshine Coast.

Talk about training

Or email luke@tagmanagertraining.com