• Jervis Koo

What is Google Tag Manager and why use it?

If you’re not that familiar with Google Tag Manager, you are probably wondering what it is and why you should use it. Let’s answer the most common questions around Google Tag Manager.

  • What is Google Tag Manager?

  • What is Google Tag Manager used for? Is it easy to use?

  • How is it different from Google Analytics?

  • Why should I use Google Tag Manager? What are the benefits?

  • What are the downfalls?

What is Google Tag Manager (GTM)?

Google Tag Manager is a free tool that enables marketers to manage and deploy marketing tags (snippets of code or tracking pixels) on our website or mobile app without having to modify the core code.

GTM works by sharing information from one data source —our website or app— with another data source (e.g. Analytics) by having data pass through Google Tag Manager.

GTM becomes really functional when we are managing multiple tags across different platforms by storing all the code in a singular place. The big bonus for us marketers is that once it's set up correctly, we can manage the code on our own without involving developers!

Is Google Tag Manager easy to use?

Google claims that GTM "helps make tag management simple, easy, and reliable by allowing marketers and webmasters to deploy website tags all in one place." This is true to a certain extent, depending on your experience with, you would require a certain degree of technical knowledge on how tags, triggers, and variables are set up. Also, if you're using GTM to install pixels for Facebook or Linkedin, you will require some understanding of how pixels work and how data is collected from these pixels. If you are using event tracking in Google Tag Manager, you will also need some knowledge about what “events” are, how they work with Google Analytics, what data is able to be tracked with events, and where to find them in Google Analytics. You will also need to know how to name your categories, actions, and labels. You read more on naming convention best practices here.

There is a learning curve when getting started but the benefits are invaluable once you're over the hump.

How does Google Tag Manager work?

There are three parts to Google Tag Manager:

Tags: Snippets of Javascript or tracking pixels

Triggers: Telling GTM when to fire tags

Variables: Additional information GTM needs for a tag and trigger to work


Tags are snippets of code or tracking pixels from third-party tools. These tags tell Google Tag Manager what to do.

Some examples of common tags used with Google Tag Manager are:

  • Google Analytics Universal tracking code

  • Adwords Remarketing code

  • Pixels (Facebook, Linkedin, Twitter, etc)

  • Heatmap tracking code (Hotjar, CrazyEgg, Inspectlet, etc…)

What are triggers?

Triggers are a way to fire tags that have been set up. They tell Tag Manager when to do what you want it to do.

e.g. firing a tag on page views, specific page or behaviour

What are variables?

Variables are additional information that GTM may need for your tag and trigger to work. An example of a constant variable that can be created in GTM is the Google Analytics UA number (tracking ID). This is especially handy for creating multiple tags that require using the same variables (e.g. pixel ID, tracking ID) without having to reenter them for every new tag created. These are some basic elements within GTM that you will require to know to start managing tags.

If you’re feeling bored reading this right now, you won't have any issues managing your tags. If you're feeling a little lost, you might need some help from someone a bit more technical!

Google Analytics vs Google Tag Manager. What's the difference?

Google Tag Manager is a tool used for storing and managing third-party codes as opposed to Google Analytics that is used for reporting and analysis. All reporting (conversion tracking, goals, traffic overview, etc) are also done within Google Analytics.

Google Tag Manager vs Google Analytics

What are the benefits of Google Tag Manager?

Once you're comfortable navigating your way around Google Tag Manager, what you're able to achieve with tracking will be on another level. You'll be able to customise the data that is sent to Google Analytics for reporting.

You'll also be able to track events such as PDF downloads, outbound link clicks, page scroll depth, specific button clicks, and even complex enhanced eCommerce product and promotion tracking. The sky's the limit! With asynchronous tag loading, using GTM also helps reduce your website's loading speed, and by having all your third-party code in one place means no more hassling developers and others in the team to install tracking codes!

What are the drawbacks?

Getting started requires some technical knowledge, even for the basic setups.

Google's documentation on how to set up Google Tag Manager takes a quick turn after the "Quick Start Guide". If you're a first time user and not familiar with basic code, this will read like gibberish.

It's a time investment

Unless you have some experience in code, you will need to get familiar by researching and testing over time.

Troubleshooting issues can be time-consuming

Setting up tags, triggers and variables sometimes require some troubleshooting if they don't work the first time around. If you're not using GTM on a daily basis, it can be easy to forget how and why certain tags/triggers/variables were set up. For the more complex tags, you will also require some fundamental knowledge of how websites are built. Google Tag Manager can definitely make your life easier if you are willing to put in the time to learn how it works.