Google Tag Manager vs. the Global Site Tag (gtag.js) – Similarities and Differences

Google Tag Manager vs. Global Site Tag: what are they, and which should you use? 

Google Tag Manager and the Global Site Tag can seem interchangeable, but they are two different tools and should be chosen wisely based on your needs.

In this side-by-side guide, we’ll learn about the Global Site Tag, Google Tag Manager, their similarities and differences, and what you can do with them. 

An overview of what we’ll cover: 

So let’s dive in!  

What Is the Global Site Tag?

The Global Site Tag is a tracking code that you install in the header section of your website. It tracks information on your website and forwards it to Google Analytics or other Google-associated tools. 

Let’s see how to access this code in our Google Analytics account. On the homepage, click on Admin Tracking InfoTracking Code

Global Site Tag tracking code in Google Analytics Admin panel

Google introduced this all-in-one code in 2017. Before that, each marketing product had its own tracking code. This meant that to use Google Ads, you needed to add the conversion.js code or analytics.js for Google Analytics.

Every tool required a separate installation of code. As a result, every new addition of code would increase the complexity of your site’s HTML and JavaScript execution. 

And what if you just wanted to see pageviews on your website? You would have to send this data to different tools and consolidate it, which is a bit of a pain.

Thus, this implementation became quite inefficient.

To solve this problem, Google came up with a more holistic solution for your tracking requirements. With the Global Site Tag (gtag.js), most of the work was cut out for the user—and you only had to install the code once.

Let’s demonstrate how this works. 

How Does It Work?

All you have to do to install this code is add the script to the head section of your website. The Global Site Tag will be on the top of all the tracking scripts. Below it, you can configure any other tools like Google Analytics or Google Ads. 

Copying the  Global Site Tag standard code to paste into the head section of your website

These tools are added to the background automatically. So when you send your data for analysis, the codes don’t need to run multiple times.

This also reduces the base code length and increases the efficiency of the data. 

What Is Google Tag Manager?

Google Tag Manager is a tag management system that acts as a common tool for running all different tracking tags, just like Global Site Tag. 

The key difference is that, unlike Global Site Tag, Google Tag Manager is not confined to Google tracking tools. Google Tag Manager accommodates a variety of other tools, including templates from community members

You can manage not only Google Ads and Google Analytics, but many other tracking Tags like Facebook Pixel or LinkedIn Tag through the single central interface of Google Tag Manager. 

Let’s see how this works!

How Does It Work?

Working with Google Tag Manager is quite easy.

You can deploy all your tracking Tags such as quotes from Google Analytics or Google Ads through its central interface. You can also put your Facebook Pixel into a custom HTML Tag and deploy it on Google Tag Manager.

In fact, you can do much more with Google Tag Manager than with the Global Site Tag. For example, you can test a code before deploying it, show a graphical user interface, control multiple versions, and access different triggers that you can utilize to deploy all this tracking.

Different types of Tags in Google Tag Manager

However, the premise remains the same. Just like the gtag.js implementation, you can define a single interaction with a trigger that you want to track, then send data to different tools.

So let’s compare them further to get a better understanding.

What is the Difference Between the Global Site Tag and Google Tag Manager?

We already know that both the tools are similar in the way that they can deploy either multiple tracking points or one tracking point to a variety of Google tools. 

In simpler words, if you want to send tracking information to your Google Ads or Google Analytics account, you easily accomplish this with either Google Tag Manager or the Global Site Tag.

But how are these tools different from one another? 

There are three main differences between Global Site Tag and Google Tag Manager: third-party tool compatibility, additional functionalities, and graphical user interfaces.

Third-Party Marketing Tool Compatibility

The first and major difference is the compatibility of Google Tag Manager with other tracking tools. 

While the gtag.js script only works with Google tools, Google Tag Manager allows you to send data to any tool that has a JavaScript-based tracking code. 

Even if Google Tag Manager doesn’t have a native integration with your favorite tools, you can usually install tracking codes via a Tag template or a custom HTML Tag. It is thus more flexible in that regard and agnostic to any tracking tools.

Google Tag Manager is more flexible and agnostic to any tracking tools.


The next major difference is the functionalities that the two provide.

The Global Site Tag doesn’t add any bells and whistles to your tracking system. What you see in your Google tools (Analytics, Ads, etc.) is exactly what you get.

Google Tag Manager provides more features in its interface. You can update new versions of your tracking implementation or revert to an old one if you find bugs. You can also test and debug your implementation using GTM’s Preview Mode to keep each version as clean as possible. 

GTM’s preview mode to test and debug the implementation

User Interface

Lastly, Google Tag Manager has a graphical user interface that is not available for the Global Site Tag. 

This means that with the gtag.js, you’ll need to do all your site’s tracking coding on your own. The Global Site Tag is effectively invisible to you as a marketer or developer except for in the website’s script. This will require at least a basic knowledge of JavaScript to configure your tools correctly with the Global Site Tag.

Hence, it becomes difficult to install some advanced functionality such as button click tracking on the Global Site Tag.

Google Tag Manager, on the other hand, has a very intuitive and user-friendly interface that requires little to no JavaScript knowledge (unless you’re building your own custom HTML Tags). 

User-friendly interface of Google Tag Manager

It’s much more approachable for marketers who don’t pull double-duty as developers.


Global Site TagGoogle Tag Manager
Compatible only with Google marketing toolsCompatible with all 3rd-party marketing tools
Simplified implementation with more limited functionalityProvides functionalities like testing of codes, version control, etc.
No graphical interface; JavaScript installation required for advanced trackingUser-friendly, graphical interface that supports advanced functionalities

When Should You Use the Global Site Tag vs. Google Tag Manager?

The Global Site Tag is just a mini version of Google Tag Manager. Based on your tracking requirements, you can choose when to use each tool.

For example, if you have a new website in which you want to set up a tool to track your visitor behaviour, you’ll need to install Google Analytics. This can be done by both Global Site Tag as well as Google Tag Manager. 

Global Site Tag

To install Google Analytics on your website with the Global Site Tag, you will be asked to add the gtag.js code in the head section. 

Adding the Global Site Tag code for installing Google Analytics to your website

Going further, if you want to drive more traffic to your website, you can choose to add Google Ads as well. This can be easily done since we already installed Global Site Tag earlier. 

Adding Google Ads code after installing Global Site Tag to your website

The Global Site Tag will then send over data to both Google Analytics and Google Ads. 

However, if you wish to expand your website tracking even further by using the Facebook Pixel, Microsoft Advertising (formerly Bing Ads), or LinkedIn advertising, then the Global Site Tag won’t support your needs. 

If you keep on adding different codes to your website, it will start creating chaos inside the HTML. It will become difficult to track which code fires which tool—a developer’s nightmare when you finally decide to clean it up later. 

Google Tag Manager

At this stage, the wise option will be to choose Google Tag Manager. This will decrease your workload significantly and also increase efficiency. 

Google Tag Manager will give you a graphical user interface that makes it easier to manage multiple codes.

Hence, it might be a better option to use Google Tag Manager instead of adding codes manually to your page. 

Which One Do I Recommend?

If given a choice, I’d definitely recommend using Google Tag Manager, even to marketers who are capable of adding the manual codes. 

Similarly, if you have a new website and want to install just one tracking system on it, Google Tag Manager will still be a preferable choice. 

It’s always better to have your website processed by a Tag management system rather than adding the codes manually. 

However, for legacy cases, it might be time-consuming to replace all the old codes with Google Tag Manager, so it would be better to continue using Global Site Tag.

Also, if you feel that you want to do the tracking manually and if you already have some modules, you could use the Global Site Tag.

But for most other cases, I would recommend using Google Tag Manager as it is a widely accepted tracking system in today’s world. 

Google Tag Manager is widely accepted in the tracking system compared to Global Site Tag

Frequently Asked Questions

Can I Install the Global Site Tag through Google Tag Manager?

In a way, yes, you can sort of install the Global Site Tag through Google Tag Manager. 

One thing to remember here is that the Global Site Tag is a mini version of Google Tag Manager itself. 

So it’s already sending data over to different tracking tools. This means you will not install the Global Site Tag into Google Tag Manager per se, but take these tools and install them into Google Tag Manager. 

So if you’re sending data over to AdWords or to Google Analytics via the Global Site Tag, then you would need to utilize the Tag template within Google Tag Manager to deploy the same tracking points with Google Tag Manager. 

🚨 Note: Do not take the gtag.js script and put it into a custom HTML Tag of Google Tag Manager. That is not a best practice and would lead to problems in your tracking.

Global Site Tag should not be put into a custom HTML Tag of Google Tag Manager

Is It Ok to Have Google Tag Manager and Global Site Tag Installed on the Same Page?

Technically, yes. Google Tag Manager and Global Site Tag are compatible with each other and can be installed on the same page. 

However, both these tools utilize some common resources that can lead to conflict in some cases. For example, the data layer is one such resource that is used by both tools.

Therefore, it is important to be careful while adding both of them together. You will also need to test the implementation of tools by checking whether the correct data is sent to these tools. 

Overall, the process is doable but complicated. That’s why I would recommend not to install them together on the same page. 

🚨 Note: For individual tools, you should use either Google Tag Manager or the Global Site Tag, but not both. If you install both of them, you will end up sending duplicate data to any tools that are connected to your website via both implementations. This could result in double-counting pageviews and other metrics, which will obviously ruin your data.


In conclusion, we can say that Google Tag Manager wins between the two—Google Tag Manager vs. Global Site Tag. 

Global Site Tag is a mini segment of Google Tag Manager. It is neither as flexible nor as powerful as Google Tag Manager. For some specific use cases, it can be the right choice. However, for most tracking requirements, you should install Google Tag Manager.

If you are new to Google Tag Manager, we have a free course to help you get started. 

Which one do you prefer between Google Tag Manager and Global Site Tag? Have you installed the Global Site Tag through Google Tag Manager? Let us know in the comments below! 


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1 year ago

I was looking for this explanation for a while and I could not find. Thanks for it. 🙂

Drew Eastmead
Drew Eastmead
1 year ago

Thank you so much – very helpful. Thank you for clarifying that if you use GTM, the global site tag is basically not necessary, and in fact, it could cause problems when they are used together. I wish Google would combine a lot of their services/tools. Analytics, Search Console, Tag Manager, gtag.js…. it’s a lot to keep track of, esp. when you have a different container ID for each tool.

Saurabh Bhatia
Saurabh Bhatia
1 year ago

What if we already have gtag.js installed on the site and now I want to upgrade to GTM. What is the procedure for that. Can we do that without any compromise on the data that we already have?

Also, can both codes be placed on the same website without any misleading data being fired to Analytics? Help!

Last edited 1 year ago by Saurabh Bhatia
1 year ago

How do I remove the Global Site Tag if I’m using GTM? For additional context, I have a wordpress site and I use elementor .

7 months ago

Thanks for the explanation. Helped me to get the basics of these two systems.

1 month ago

Thanks, Julian! Very helpful

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