Google Click Identifier (GCLID)

A GCLID, short for Google Click Identifier, is a parameter that Google Ads auto-tagging adds to the landing page URL after someone clicks your ad.

By Berend Vrakking, founder of Product Metrics. Updated 7 October 2026.

Example

One ad click, as the landing page URL shows it
Part	Value
URL the ad links to	https://shop.example/trail-runner-2
URL the visitor lands on	https://shop.example/trail-runner-2?gclid=abc123example
Click ID (the value after gclid=)	abc123example

Auto-tagging bolts the parameter on after the click; your shop never builds it. Illustrative data.

For one product, and for an account

The GCLID is the thread between a purchase and the ad click behind it. Google says the parameter is required for Google Ads website conversion tracking; it also links data between Google Ads and Google Analytics, and works with offline conversion tracking.

Auto-tagging is an account setting, and Google turns it on by default for new accounts. A GCLID only helps if it survives until the order is recorded. Full Signal Tracking keeps the click ID and sends it to Google Ads with the purchase; Google Ads then does the attributing, because Product Metrics is not an attribution tool.

Common mistake

Redirecting visitors and losing the parameter on the way. Google says the GCLID has to reach the final landing page for conversions to be tracked, so a redirect that strips it takes the conversion with it.

Questions

What does GCLID stand for in Google Ads?

It stands for Google Click Identifier. When auto-tagging is on, Google Ads adds it as a gclid parameter to the URL people click through to your site.

How do I find my GCLID?

Look at the landing page URL after an ad click. With auto-tagging on, it carries a gclid parameter, as in Google’s own example, www.example.com/?gclid=123xyz. The value after gclid= is the click ID.

What is a GCLID number?

It is the click ID itself, the string after gclid= in the landing page URL. Google says the value identifies the campaign along with other attributes of the click.

Sources

Keep reading

First-party cookieWhere a click ID can be kept after the landing page.
Full Signal TrackingSee the click ID travel with an order to Google Ads.
Enhanced conversions vs server-side trackingCompare two ways to send purchases to Google Ads.
Last click attributionHow Google Ads shares credit between the clicks before an order.