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

GTM and GTag are two different tracking methods of achieving the same goal. So which one should you choose? In this video we are going to show you the key differences and similarities between using Google Tag Manager vs. GTag for your tracking implementation, so you can decide which one is right for you.


Gtag – Global site tag

Google Tag Manager

Hey there measuregeeks. Julian here back with another video for you. Today, we want to talk about the Gtag, the global site tag versus Google Tag Manager, the similarities, differences and what we can do with both. All and more coming up.

What is the Global Site Tag?

All right, let’s jump right in. What is this all about? Well, if you install Google Analytics on your new website, you go to the tracking information. And there is where you find the Gtag, the global site tag. This is the tracking code that most of the tools of Google want to nowadays to install in the head section of your website on all the pages.

This will start tracking your information on your website and transfer it over to Google Analytics to the Google Ad system, floodlight tags or Google Optimize. So what is this Gtag all about? It was introduced by Google in 2017 because previously, they had different products in the marketing suite. So all of these different products actually had their own tracking code.

So for Google ads, that was, for example, conversion js, for Google Analytics, it was analytics js. Now obviously, this led to a lot of confusion because once you started building your tracking and adding tools from the Google line, you would start implementing all these tracking codes onto your page.

A lot of different tracking codes that convoluted your account your HTML, your JavaScript execution, and at the same time, it wasn’t quite efficient.

Because what if you wanted to just check a page view, you’ve already done this once now you need to send it over to these other different tools again and again. So Google came up with a new way to consolidate all of these different tracking scripts into one which takes care of the heavy lifting, so you only need to install the code once. The Gtag is nowadays the standard that Google wants you to install as the code onto your website for the tools to track the way it works is actually you have a base code that you place on the top and underneath, you can configure different tools like Google Analytics, or Google ads or the optimized tag.

And then these will be loaded in the background. And then you can send data over, the page view to Google Analytics and to Google ads for retargeting, for example, all the conversions to both tools. And obviously, this makes it a bit easier and keeps the whole tracking thing a little bit shorter inside of your HTML. So you don’t convolute your whole codebase.

What is Google Tag Manager?

So what then is Google Tag Manager all about? What is Google Tag Manager? It is a tag management system. With Google Tag Manager, the premise is that you would have one container snippet, which you place on all your pages of your HTML. And then you would be able to deploy all your tracking tags such as quotes from Google Analytics, Google Ads, but also Facebook Pixel, LinkedIn tag, and so on through the central interface of Google Tag Manager. This is not restricted to any Google products, although Google Tag Manager is a product from Google.

But you can also take the Facebook Pixel, put it into a custom HTML tag. And then it will be deployed through Google Tag Manager through this one central snippet that you have installed. You can do much more with Google Tag Manager, then with the G tag not only deploy the code, but you have extra benefit of testing the code before. You have this graphical user interface. You have version control, different triggers that you can utilize to deploy all this tracking.

But the premise is really also the same, like the Gtag you can define one interaction with a trigger that you want to track and then send different quotes out at the same time. So to Google Analytics to send the event to Google ads, maybe a conversion to the Facebook tag, or the link in insights tag. So really, you can do the same thing with Google Tag Match than with the Gtag.

What’s the Difference and Similarities?

So where are both tools similar and where are they different? Well, we already talked about the similarities really. Both of these tools, these tracking scripts can deploy multiple tracking points or one tracking point to multiple tools. So when you want to send a page view on to Google ads and Google Analytics, you can do this with Google tag manager or the global site tag.

But there’s where it really already ends. Because the global site tag is only there for Google products that Google products are connected to the global site tag. So you can send data to Google ads or to Google Analytics, but not to the Facebook Pixel. Google Tag Manager is more flexible in that regard. It is agnostic to any tools out there. So you’ll be able to send over data to any kind of tool that is JavaScript based and has a tracking code that you can install, either through a tag template or through the custom HTML tag. And obviously, Google Tag Manager brings in more functionality like the management functionality, the version control, the testing, and so on, and so on. So it’s much more sophisticated in that regard.

Now, when we compare both of these tools, again, we see that the global site tag is not really up to par with Google Tag Manager. It has some similarities with sending tracking out, but it doesn’t have a graphical user interface. So you would need to do still all your coding within the code.

And you would need to know a little bit of JavaScript in order for it to work and configure it correctly. And it’s not that easy to install any kind of extra functionality, advanced functionality, such as button click tracking with the global site tag.

When Should You Use Gtag or GTM?

So in the end, the global site tag is really just a mini version of Google Tag Manager, and can be really compared to it. So when would you utilize the global site tag? And when would you use Google Tag Manager?

Well, let’s imagine you have a brand new website and you just want to stop Tracking some information about how users behave on your website, you want to install Google Analytics. So you go over to Google Analytics, there is where you will find the Gtag to install in the head section sounds easy. You place it there all is good. But what if you grow, you want to drive traffic to the website, so you go with Google ads. And they’re also asked you to install a global site tag onto your page.

It is easier this time because you already have it installed, you just need to add one line of code. And then it will actually send data over to Google Analytics and to Google ads. Now what if you grow even further, you want to do Facebook advertising, you want to do Bing Ads, you want to do LinkedIn advertising? What tool do you use now? At that stage, I would say it is better to go with Google Tag Manager.

Why? Because manually installing these different codes would again convolute your website code and it would be just sheer chaos inside of the HTML because you don’t know what fires when to which tool. Google tag manager can take care of this for you. And you have a nice graphical user interface where you can manage all your code. So at that stage, I would say, maybe look at Google Tag Manager as an alternative to placing these codes manually on your page.

Which One Do I Recommend?

So which tool would I recommend if I had the ability to install the Gtag or everything to Google Tag Manager? Well, I would choose Google Tag Manager definitely. Even at the beginning, even if it’s your first website, and you don’t have any tracking installed, you want to install just one code. It is a far better practice to do this through a tag management system, rather than trying to put these codes on manually. Now, there might be legacy cases out there where you want to utilize the global site tag instead of Google Tag Manager.

There might be also a use case where you say I don’t want to use Google Tag Manager at all. I want to track my code differently or I have a module that I have written myself onto page, I manage these codes differently, yes, then go with the global side tag. But in most of the cases, I would recommend to go with Google Tag Manager just because it’s best practice. And it is the way to install tracking nowadays.

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

So some questions at the end, can I install the global sidte tag through Google Tag Manager? Yes, kind of. Remember, the global site tag is like a mini version of Google Tag Manager. So it’s already sending data over to the different tracking tools. So 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 with the global site tag data over to AdWords or to Google Analytics, well, then you would need to utilize the tag template within Google Tag Manager to deploy the same tracking points with Google Tag Manager.

Please don’t take that global site tag that you see in the interface of Google and put it into a custom HTML tag and deploy it through Google Tag Manager. That would lead to problems maybe, and also is just not best practice.

Is it ok to have GTM and the Gtag installed on the same Page?

So is it okay to have Google Tag Manager installed and the global site tag at the same time? Well, the general answer is yes, these are compatible with each other. But they also utilize some of the same resources. So for example, the Google Tag, Google Tag Manager uses something called the data layer.

And the global site tag also uses something called the data layer. So there are some shared resources. And these can also lead to conflict. So you need to be careful that you don’t mix and match and you always would need to test your implementation to see if the right data gets sent over. And this makes the whole case a bit more complicated, doable, but complicated. Generally, I would recommend not to have both tools on the website at the same time, although it is possible.


So in conclusion, who wins Google Tag Manager versus Google analytics? I will clearly say Google Tag Manager is the tool to install tracking nowadays. The global site tag is there for convenience sake, but only at very specific use cases. So I would always go with Google Tag Manager when I install Google tools like Google ads, Google Analytics, or Google Optimize.

This is my choice when it comes to deploying tracking. Nowadays, the global site tag is really just a mini version of Google Tag Manager, not as flexible, not as powerful as Google Tag Manager. So if you have a specific use case, and you want to stay small, and Google Analytics is all you need on your website, then maybe go with the global site tag, that’s all fine. But if you want to take tracking seriously and track data on a consistent basis, then definitely check out Google Tag Manager, if you haven’t yet.

We actually also have a course on this channel, Google Tag Manager for beginners dive into it. I’m going to link it up right over there.

Let me know in the comments below if you still have questions about the global site tag and the differences to Google Tag Manager, which one do you use? I’d love to hear from you in the comments down 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
10 months 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
7 months 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 7 months ago by Saurabh Bhatia
6 months 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 .

16 days ago

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

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