An Overview of Google’s “GCLID”. Everything You Need to Know

April 08, 2019

Arguably the most important part of paid search is tracking – it underlies all the keywords, ad groups, and conversions we are trying to optimize for our business. That’s where the GCLID comes in. The GCLID, or Google Click ID, is a unique identifier in your ad URL where your keyword, ad, and other campaign data are stored. When Google Ads is connected to Google Analytics (GA), the GCLID gets passed to GA which then decodes and reports on the associated Google Ads information.

These days, Google Ads has an option to simply “auto-tag” ads with the GCLID – Google’s answer to standardizing utm parameters. With Auto-tagging enabled, when a user clicks on your ad, a GCLID is automatically appended to the Final URL (with the exception of Click-to-Call ads which are not associated with a landing page URL).

One can spot a GCLID by the “gclid=” that appears in the landing page URL. 

This GCLID becomes associated with the cookie that also gets saved to your computer. Cookies are standard protocol for websites and they allow the website to remember returning users for a more fluid experience. This connection made possible by the GCLID is what allows GA to attribute on-site actions back to your paid search campaigns.

In the early days of paid search, advertisers had to manually tag their URLs with utm parameters. This was far from ideal as it left a lot of room for mistakes – these are case-sensitive and could vary depending on a certain advertisers’ preferences. Manual tagging is also limited in that you can only tag your URLs with utm_campaign, utm_source, utm_medium, utm_content, and utm_term (keyword). The parameters which are associated with the GCLID are:

  • Source
  • Medium
  • Campaign
  • Ad Group
  • Keyword
  • Query Match Type
  • Ad Creative
  • Placements

To start using the GCLID, first you need to be able to track on-site actions with GA so make sure the sites you want users to convert on have the GA tracking tag added to your site. GA is a powerful tool in itself because it can track conversion goals beyond the scope of those on Google Ads, report metrics such as Bounce Rate, Avg. Session Duration, and Pages/Session, and much more.

Next, you should link your Google Ads and GA accounts so that GA can attribute back conversions to the responsible proper campaigns, ad groups, and keywords in Google Ads.

Once linked, you can enable auto-tagging in your Google Ads account under “Account Settings > Preferences > Tracking > Auto-tagging > Yes”.

Auto-tagging is what appends the GCLID to your landing page URL after a user clicks your ad. And voila – if set up correctly, a GCLID will be appended to the final URL after a user clicks on your ad and lands on your site.


The simplest way to check if auto-tagging is properly enabled is to click on your ad and see if the GCLID is appended to the URL. Please note that you will be charged for an ad click since this is treated as a regular click on your ad. If the GCLID does not appear, then something probably went awry during the setup.

Another easy check is to see if there are huge discrepancies between clicks and sessions in GA under Acquisition > Google Ads > Campaigns. Small discrepancies are expected due to the different ways Google Ads counts Clicks and GA counts session. But if you’re worried data is far from normal, please refer to this article on GA and Google Ads data discrepancies

To definitely check if it’s working, you can follow these steps outlined by Google using Chrome Developer Tools – which can also troubleshoot any problems your experiencing.

If you aren’t using Auto-tagging on your Google Ads account, and you have GA, you should instrument Auto-tagging ASAP. Google Analytics won’t be able to track accurately until the date you set up this tracking.

For more information on the nuances between Google Ads and GA please check out this article.