The Magic of Cookies with Google Tag Manager

Updated: April 3rd, 2025

Cookies are a vital aspect of the average user’s internet experience (of course, there are some side effects, too). Still, the initial idea was novel – to have a more personalized experience across the web.

Cookies are handy for marketers, too. They retain information that helps better understand users’ browsing behavior, which can then be used to improve your marketing efforts.

By default, Google Analytics and other analytics tools use cookies to track a user’s behavior on your website. Unfortunately, I still see many marketers (working with GTM) suffering from being unable to fire Tags for returning visitors or after 4 page views, etc.

But this shouldn’t be a problem since you can easily use tag managers to set and retrieve data from cookies. In this blog post, I’ll show you how to efficiently utilize cookies with Google Tag Manager and take your web tracking to the next level.

I remember when I was starting to learn GTM. It felt like a real level-up when I realized I could set and read cookies without a developer’s help. It added much more flexibility and freedom to my tag management.

What if I need to fire a specific Pop-up if a visitor initially landed on my website from Google Ads AND has already viewed five pages? Not a problem!

Before we continue: this topic is also thoroughly explained in the Intermediate GTM Course

If you prefer video content over blog posts, consider enrolling in my Intermediate Google Tag Manager Course. In it, I will uncover many GTM features/tips/tricks that intermediate users often miss. Also, you will get a proper introduction to some technical topics that will help you go to the next level with GTM (including cookies).

Why should you even bother with cookies? Few Examples

By setting and reading cookies with Google Tag Manager, you can start creating more sophisticated triggers, such as:

• A visitor has viewed five pages. Let’s show him a pop-up with a special offer!
• Suppose a visitor on your SaaS (Software as a Service) website is actually a user but is currently browsing without logging in. Nevertheless, they still have a cookie with the value “registeredUser=true”. This condition is good to use for your trigger.
• A visitor has landed on your website via an affiliate link. You can preserve the affiliate ID in the visitor’s cookie with each page view. Here’s the full guide on how to do that.
• Do you have a pricing page with a price calculator? Let’s bind the calculator’s results (price) to that particular visitor with the help of a cookie. This way, you’ll see how visitors with different price ranges behave on your site.

Pretty neat, huh?

So What’s the Plan?

To create a cookie in Google Tag Manager and use it in tags/triggers, follow these steps:

1. Create a cookie with a tag
2. To access that cookie, create a 1st-party cookie variable
3. Create a trigger where the condition contains a 1st party cookie variable.
4. Fire a tag based on a trigger from a bullet point from step no. 3.

Let’s take a closer look at each step.

Set cookies with Google Tag Manager

The first thing you need to do is to create a custom HTML tag when setting up a cookie. It contains JavaScript code that defines the cookie’s name, expiration time, etc.

<script>
(function(){
    var cookieName = "visitorFromGoogleAds"; // Name of your cookie
    var cookieValue = "true"; // Value of your cookie
    var expirationTime = 2592000; // One month in seconds
    expirationTime = expirationTime * 1000; // Converts expiration time to milliseconds
    var date = new Date();
    var dateTimeNow = date.getTime();

    date.setTime(dateTimeNow + expirationTime); // Sets expiration time (Time now + one month)
    var date = date.toUTCString(); // Converts milliseconds to UTC time string

    // Extract base domain
    var domainParts = location.hostname.split('.');
    var baseDomain = domainParts.slice(-2).join('.'); // Get the last two parts of the domain

    document.cookie = cookieName + "=" + cookieValue + "; SameSite=None; Secure; expires=" + date + "; path=/; domain=" + baseDomain; // Sets cookie for all subdomains
})();
</script>

In the script above, there are three variables that you should edit:

• cookieName – you should give it a meaningful title, e.g., visitorFromGoogleAds, affiliateID, pageviewCount, etc.
• cookieValue – In the case of visitorFromGoogleAds possible values can be true or false. For example, affiliateID cookieValue can be 2385437, and pageviewCount cookie’s – 5.
• expirationTime defines when the cookie expires. 2592000 is 30 days converted to seconds (30 days * 24 hours * 60 minutes * 60 seconds * 1000 milliseconds). If you want the cookie to expire after the session ends (when the browser window is closed), remove expires=”+date+”; from the end of the script. Remember that Google Chrome still runs in the background when you close the browser window. Thus, the cookie will “live” longer.

Now, you need to decide when you want to set that cookie. For example, should this “set cookie” script fire when the URL contains ?gclid= (meaning that a visitor landed via a Google Ads campaign)?

Say we want to set cookies for those visitors who have found our website via Google Ads. In that case, we need to create a trigger with the following settings.

When a person clicks any Google ad, the destination URL contains ?gclid=XXXXXX. That’s the reason behind this trigger’s condition.

Test The Cookie

After creating a custom HTML tag with the cookie-setting script and its trigger, you should next test the implementation with Preview and Debug mode. Make sure that the tag fires ONLY when the URL contains ?gclid=. If you’re new to Preview and Debug mode, read this comprehensive guide.

Now, let’s check whether a cookie has been correctly set. There are two main ways to check cookies – the browser’s built-in feature (developer tools) or a plugin.

I use a Chrome plugin called EditThisCookie (also available for Opera users). This simple and intuitive extension lets me quickly check which cookies are currently used and what data they contain.

If you haven’t already installed it, download it here. You’ll need to find something on your own if you’re using a different browser.

Anyway, let’s get back to EditThisCookie. Once you have installed this extension, a cookie icon will appear next to the Menu icon (in Chrome).

Go to the website you’re working on, click the EditThisCookie icon, and you’ll see an expanded list of all currently used cookies. Look for a cookie named visitorFromGoogleAds. This little piece of data will help us do the magic in further chapters of this blog post.

Read The Cookie

Now, we need to “teach” Google Tag Manager read the cookie and make it available as a variable. Go to your GTM account, open the list of Variables, and create a new user-defined variable with the following settings:

This variable searches for cookies with the title visitorFromGoogleAds. If it spots one, GTM will read its value and make it available in the Variables tab of the Preview and Debug console.

Following the above steps enables you to use visitorFromGoogleAds variable in any GTM tag or trigger, like in the example below:

Example – Fire a Tag on 3rd Page View

Firing a specific tag after a certain number of pageviews is one of the most popular use cases of cookies with Google Tag Manager. For your convenience, I have prepared a GTM Recipe with a ready-made script that counts the number of page views and fires a trigger after 3. But if you’re eager to understand the details, continue reading.

DOWNLOAD THIS GTM RECIPE

Let’s Count Page Views

First, you’ll need to create a custom HTML tag that counts page views. Every time a page refreshes, this script searches for cookie pageviewCount and increments its value by 1.

<script>function setCookie(name, value, expires) {
var cookie = name + "=" + value + "; path=/; domain=." + location.hostname.replace(/^www\./i, "");

if (typeof expires !== "undefined") {
var now = new Date();
now.setTime(now.getTime() + expires * 24 * 60 * 60 * 1000);
cookie += "; expires=" + now.toUTCString();
}

document.cookie = cookie;
}

function getCookie(name) {
var cookies = document.cookie.split(";"),
toReturn;

for (var i = 0; i < cookies.length; i++) {
var cookie = cookies[i].trim();
if (cookie.indexOf(name + "=") === 0) {
toReturn = cookie.substring((name + "=").length, cookie.length);
}
}

return toReturn;
}

(function() {
var pageviewCount = getCookie("pageviewCount");

if (typeof pageviewCount === "undefined") {
pageviewCount = 1;
} else {
pageviewCount++;
}

setCookie("pageviewCount", pageviewCount, 30);

})();
</script>

The cookie (set by this JavaScript) expires after 30 days. You can easily change its duration by editing setCookie(“pageviewCount”, pageviewCount, 30).

Set this custom HTML to fire on all pages. Refresh Preview and Debug mode, open the EditThisCookie plugin, and check whether the cookie was saved. The cookie’s value should increase to 2.

If you want this cookie to be valid only for that visitor session, here’s a modified script (I’ve removed all parts related to the expiration date). Keep in mind that Chrome handles cookies a bit differently (compared to other browsers).
Even if you close the tab or window, Chrome still might keep running in the background. Therefore, session cookies might still be valid.

<script>function setCookie(name, value) {
var cookie = name + "=" + value + "; path=/; domain=." + location.hostname.replace(/^www\./i, "");

document.cookie = cookie;
}

function getCookie(name) {
var cookies = document.cookie.split(";"),
toReturn;

for (var i = 0; i < cookies.length; i++) {
var cookie = cookies[i].trim();
if (cookie.indexOf(name + "=") === 0) {
toReturn = cookie.substring((name + "=").length, cookie.length);
}
}

return toReturn;
}

(function() {
var pageviewCount = getCookie("pageviewCount");

if (typeof pageviewCount === "undefined") {
pageviewCount = 1;
} else {
pageviewCount++;
}

setCookie("pageviewCount", pageviewCount);

})();
</script>

Cookie variable and trigger in Google Tag Manager

Since we created a pageviewCount cookie, it’s time to “teach” Google Tag Manager to read the cookie and make it available as a variable. Go to your GTM account and open a list of Variables. Create a new user-defined variable with the following settings:

Next, go to Triggers and create a new Page view trigger with the following settings:

This trigger will fire when the cookie’s value is greater than or equal to 3.

That’s it! You can now assign this trigger to any tag you want, whether it is a pop-up, Google Analytics event tag, or whatever. I’ll leave it entirely to your imagination.

Delete a Cookie

If you want to delete a particular 1st-party cookie, you need to set its expiration time to a date in the past, e.g., January 1st, 1970. Such cookies cannot exist. Therefore, they immediately expire.
Here’s a script that you should use:

<script>
(function() {
var name = 'yourCookieName'; // REPLACE yourCookieName WITH THE NAME OF THE COOKIE YOU WANT TO DELETE
var path = ''; // If needed, replace this
var domain = ''; // If needed, replace this
document.cookie = name + "=" +
((path) ? "; path=" + path: "") +
((domain)? "; domain=" + domain: "") +
";expires=Thu, 01 Jan 1970 00:00:01 GMT";
})();
</script>

In the 3rd line of the code, change yourCookieName with the name of a cookie you wish to delete. This code should also be implemented via GTM Custom HTML tag and fired whenever you need to delete a cookie (e.g., after a conversion, opt-out or something else).

Also, if your cookie has a specified domain and path, insert the values in the ‘path’ and ‘domain’ variables (in the JavaScript code). But you can start by keeping those fields (in the 4th and 5th lines) empty and see if it works.

A

Few More Ideas

Here’s food for thought if you still don’t know how to leverage cookies in your marketing stack. I hope these examples will help you break the ice:

• If you run an affiliate program, you already know that visitors come to your site via affiliate links (which contain a unique affiliate ID). You can fetch that data from the URL, set it as a cookie, and send it to Google Analytics as Custom Dimensions. This way, you’ll see how well/terrible affiliate traffic is converting. Also, you can identify which affiliate partner is driving the most engaged traffic.
• If a person purchased a product on your site, save this fact as a cookie. Then, create a pageview trigger that blocks pop-ups (irrelevant to recent buyers).
• If you run a SaaS business, ask developers to set various data about the user in cookies. Even if the user has logged out, you can still identify them visiting your website/blog/etc. and send that data to Google Analytics as custom dimensions. But be aware of PII limitations.

Not all 1st party cookies can be read with Google Tag Manager

This applies not only to GTM but to client-side JavaScript in general. If you’re already familiar with cookies, you know that all the cookies (set on that page) can be seen by going to your browser’s developer tools. I’m using Chrome. Therefore, the full path to that part is Chrome’s Menu > More Tools > Developer Tools > Application > Cookies.

Then choose your domain. You should see something like this:

Those are the 1st party cookies you could potentially use in Google Tag Manager. Various scripts and other functionality on your site set those cookies to your visitors’ browsers. However, not all of them are accessible by JavaScript in your browser (including GTM).

If a cookie has a checkbox in the HttpOnly column, GTM cannot access its value. This means that a 1st party cookie variable will return undefined.

Working with cookies and Google Tag Manager: Final Words

It’s pretty easy to manage cookies with Google Tag Manager. First, you must fire a custom HTML tag that sets the cookie with a particular value (there are also custom templates available in Google Tag Manager’s gallery). Then you need to create a 1st party cookie variable within GTM.

This variable’s value can be transferred to other tools (such as Google Analytics) or used as a firing condition within a trigger.

If you’re looking for ways to fire a particular tag after 3 page views, or for those visitors who have visited a specific page, then cookies should be your weapon of choice. Another solution is browser storage (localStorage and sessionStorage), but that’s a topic for another time.

Do you know more tricks for using cookies with Google Tag Manager? Let me know in the comments.

By the way, I’ve noticed some people asking me this question, “does Google Tag Manager use cookies by default?”. They are worried about various privacy regulations. To answer that, I’ve published a blog post.