GCLID: What It Is and How to Test It

If you have been running Google Ads campaigns of any kind for a while (AdWords, Shopping or Display), you may have come across (or had to deal with) the GCLID parameter. But do you really know what it is, how it is activated or how to check that it is working correctly?

In this article we are going to explain everything in the simplest way I know. We will start with an introduction and an explanation of basic concepts (if you already know them, you can skip it and go straight to point 4) before getting into the real goal of the post, which is to explain, through a real case, how to detect the problem and check that the solution works correctly in the simplest way.

Shall we get down to it?

May 2025 update:

Although the theory explained below is still completely valid (and you should read it to understand everything properly), the truth is that 4 years have passed since I wrote the article.

That means that, for example, the extension Tag Assistant we used to test the parameter has changed.

That is why I have recorded a video with the current process, which is the one you have below.

That said, before watching it, I strongly recommend that you take a look at the original text content, as it will help you better contextualize everything I explain in the video.

And one more tip that I mention at the end of the video but that is not in the original article text:

As of today, given the difficulties that browsers, devices and extensions add every day to analytics and advertising tracking, if you use Google Ads you need to tag your campaigns in two ways:

• Using Google Ads auto-tagging.
• Adding UTM tagging to all URLs.

It is the way to improve the tracking of your Google Ads campaigns in Google Analytics.

With that, I close this article update. Below is the original text, whose concepts remain fully valid.

Concepts about the GCLID parameter and automatic campaign tagging

Before starting with the case itself, it is worth reviewing some concepts we will use later throughout the article. The first thing is to explain what Google Ads auto-taggingis, the feature that will generate the GCLID parameter.

Auto-tagging in Google Ads

What it is

As we can read on the Google support page, auto-tagging is a Google Ads feature that adds the GCLID parameter (Google Click Identifier) to all URLs in the account. This parameter makes it possible to share click information between Google's different marketing tools, particularly between Google Ads and Google Analytics.

How to enable it

It should be noted that it is disabled by default in all accounts and that we are the ones who have to enable it voluntarily. To do so, we go to the Google Ads account where we want to activate it and, once there, enter the settings, as shown in the image:

In addition, we will need to link the Google Analytics and Google Ads accounts between which we want to share information from the Google Analytics property administration:

What advantages it offers

Mainly being able to import metrics from one tool into another, thus adding Bounce Rate or Time on Page -native to Google Analytics- to Google Ads reports:

In the same way, we will have Impressions or Clicks (native to Google Ads) in Analytics reports:

Having the End-to-End view of users who click on our ads and what they finally do on our website (bounce, conversions…) is obviously quite essential, don't you think?

The GCLID parameter

Now that we know what auto-tagging consists of, let's see how Google executes it, which is through this famous parameter.

What it is and what it consists of

As we said before, the GCLID is a unique parameter that Google adds to all Google Ads campaign URLs -as long as we have auto-tagging enabled, let's not forget- and that allows information exchange between the company's marketing platforms.

The campaign URL would become:

• Original URL we add to the campaign: https://www.yopongoelhielo.com/es/3-whisky
• Example of URL parameterized by Google: https://www.yopongoelhielo.com/es/3-whisky?gclid=123456789

The bold part of the previous URL is what Google adds to our original URL, the GCLID. This value is unique for each click and allows it to have certain values associated with it.

What it actually does

The GCLID added in Google Ads is identified in Google Analytics, which will add the following dimensions to the user's session:

• Source
• Medium
• Campaign
• Ad group
• Keyword
• Search term
• Match type
• Device type
• And a few more

Advantages

The main advantage of having it enabled is convenience: this way we avoid having to add UTM parameters to all campaign URLs, also avoiding misspelling, incorrect tagging or even forgetting to add campaign tracking. In general, using it is highly recommended.

How to activate it

By activating auto-tagging as we mentioned in the previous point, that is enough. You do not need to do anything else for the GCLID parameter to be added to your campaign URLs.

With this we finish the introductory section and get into the heart of the matter: the example case. Are you coming with me?

The detected problem

Once we have the basic concepts clear, we get into the real case that will serve as an example. At Yo pongo el hielo we had been running several AdWords campaigns for quite some time and wanted to launch a Google Shopping campaign.

We had never had tagging problems with AdWords, but when checking the Shopping campaign data we came across this:

Google Analytics

We see that in the Analytics reports the platform's own metrics were not appearing for us, unlike in the rest of the AdWords campaigns:

Google Ads

Well, if they do not appear in Analytics, no problem, we will check them in Google Ads and that's it, we thought. How naive!

As we can see, neither Google Analytics nor Google Ads gave us the performance metrics of users coming from the Shopping campaign on the page. And that, when you are investing money, is a major problem.

The manual solution: workaround

We did not want to stop the campaign. We checked that everything was properly configured on the three platforms: in addition to Google Ads and Analytics, we also reviewed Google Merchant, Google's platform for managing the Shopping product catalog. It is the place from which feeds are uploaded and is therefore essential for working with the channel. We found nothing wrong in any of the platform configurations.

Then we assessed what options we had: here Analytics and Merchant were our friends. Be careful because this solution was a patch while we figured out what was going on and it is NOT the definitive one (the good one is further down in point 4).

Adding a parameter to the feed

The first thing we did was add a parameter with which to identify traffic coming from Shopping in Google Analytics:

• Original URL: https://www.yopongoelhielo.com/es/1714-salitos-blue.html
• URL parameterized by us: https://www.yopongoelhielo.com/es/1714-salitos-blue.html?from=GS

By adding that parameter to all the URLs in the product feed, we had already identified traffic from that channel.

Advanced filter in Google Analytics

Next, we added an advanced filter in the Analytics view to change the Medium of traffic coming from Shopping (by default Analytics detected it as organic traffic):

This way, in Analytics reports we could already have a bit more info:

Segment in Google Analytics

But we wanted a bit more information about Shopping users, so with this configuration, we also created a segment to identify them and thus be able to see their behavior:

And this is the result:

Ok, after this workaround of a couple of hours of work, we already had the necessary information, but is it an optimal solution? We believe not; it is only to get by while we investigated the root of the problem. And this is what we did.

The correct solution

After investigating the possible causes for not receiving Shopping data correctly in Analytics, we ruled out that it was an account linking problem, since the rest of the AdWords campaigns in the same Google Ads account did work normally.

With auto-tagging as it was, what remained was to check how it worked, for which we analyzed what was happening with the GCLID parameter.

Checking and testing the GCLID parameter

To check what was happening with the GCLID on our website, we used the extension Tag Assistant for Google Chrome:

Installing Tag Assistant

The first thing is to go to the extension page:

We install it and go to the URL we want to analyze, which obviously should be one of those included in the Shopping feed. In our case it was the following:

• https://www.yopongoelhielo.com/es/1714-salitos-blue.html?from=GS

Checking the GCLID

Next we open the Tag Assistant extension and activate it:

We add a test GCLID parameter to the URL, which will look like this:

https://www.yopongoelhielo.com/es/1714-salitos-blue.html?from=GS&gclid=test1234

We have added the bold characters. We made up the parameter value, it could be another one, for example:

• gclid=test
• gclid=123456
• gclid=elqueyoquiera

We reload the page with the extension enabled and see all the Google tags we have implemented on the URL:

As you can see, we have quite a few implemented. In simpler projects you may see fewer.

We click on the Analytics account tag that we have linked to Ads and in which we are not receiving the data. In our case it is tag number three. We will see something like this:

And now the magic begins.

Detecting the problem

We click on "Page Request":

Once inside, we click on URL:

Finally, we list the parameters from the icon at the top right and focus on the one called "dl":

Voilà! Here we have it. We see that the "from=GS" parameter remains but the GCLID has disappeared. And that is the problem, because if the Analytics tag does not receive it, it is unable to assign the corresponding Google Ads values to the session.

Well, now we know where the error is. Now we have to find out why it is happening and how to fix it.

Developing the solution

Looking at the URL in detail, we see that the one we had loaded in the browser was:

• https://www.yopongoelhielo.com/es/1714-salitos-blue.html?from=GS&gclid=test1234

And the one the Analytics tag received is:

• https://www.yopongoelhielo.com/es/alcopop/1714-salitos-blue.html?from=GS

Looking at the bold parts, we see that apart from losing the parameter along the way, a directory has been added to the URL, "/alcopop/". What does this mean? Well, that the product URL we send to Shopping has a redirect, which adds the product category.

Redirects are very dangerous in general and for parameters and Google in particular and, in this case, it causes the GCLID to be lost. Fortunately, the solution is simple: just regenerate the feed URLs correctly, adding the category.

Testing the solution

Once solved, we will have to test it again. To do this, we will go to any of the new URLs in the feed (which already contain the category) and add a test GCLID:

• https://www.yopongoelhielo.com/es/alcopop/1714-salitos-blue.html?from=GS&gclid=testfinal

Let's see what our friend Tag Assistant shows us now:

We see that the dl parameter now no longer loses the GCLID, since we have removed the redirect that was deleting it.

And once fixed, what happens in Google Analytics? Well, let me show you:

And in Google Ads?

Well, it seems the problem is now solved. In my opinion, the important thing about the case has been discovering the cause (the GCLID being dropped) and the investigation process through Tag Assistant. What do you think? Did you know this system? Do you use a better or simpler one?

Finally, I hope that if you ever find yourself in a similar situation, this mini guide helps you. That is why I created it.

Talk to you soon.