UTMs in GA4

December 17, 2025
  • First Published: December 17, 2025
  • Last Modified: December 18, 2025

You’ve likely heard “UTM parameters” tossed around in almost every marketing meeting you’ve attended this year.

There’s a very good reason for that.

If you aren’t using them—or if you’re using them inconsistently—your Google Analytics 4 (GA4) data is probably lying to you.

When parameters are set up correctly, they ensure your traffic is “bucketed” into the right categories.

Without them, your hard-won email traffic might end up in the “Unassigned” abyss, or your social media influencer campaign might just look like “Direct” traffic.

If you’re tired of guessing which campaigns are actually driving results, it’s time to get a handle on the Urchin Tracking Module. (Yes, that’s actually what UTM stands for!)

Table of Contents

What Are UTM Parameters?

In the simplest terms, UTM parameters are small bits of text added to the end of a URL.

They don’t change the destination of the link; they simply tell GA4 exactly where that visitor came from and what prompted the click.

There are five main parameters you can work with, though the first three are generally considered the “standard” requirements:

UTM Source: Identifies the platform (e.g., google, youtube, newsletter).

UTM Medium: Identifies the marketing tactic (e.g., cpc, email, social).

UTM Campaign: The specific name of your promotion (e.g., summer_sale_2024).

UTM Term: Mostly used for paid search to identify specific keywords.

UTM Content: Useful for A/B testing or differentiating links within the same email (e.g., header_button vs footer_link).

Pro Tip: GA4 is incredibly sensitive to capitalisation. To a machine, email, Email, and EMAIL are three completely different channels. Pick a standard—usually all lowercase—and stick to it religiously across your entire team. Otherwise you’re gonna see these split out in your marketing and potentially even suffer from cardinality.

The benefits of UTMs

The primary advantage is consistency; by following a structured naming convention, you ensure that your data is clean and comparable over time.

This allow you to accurately measure the performance of specific channels and individual campaigns, ensuring that every click is funnelled into the correct “bucket” within your GA4 reports.

Without this level of detail, your attribution becomes messy and unreliable.

Furthermore, UTMs are essential for capturing data that would otherwise be lost; for instance, they act as a bridge for non-web documents (like PDFs or Word files).

Since these files don’t naturally send referrer information, UTMs are the only way to prevent this valuable traffic from being miscategorised as “Direct,” giving you a much clearer picture of your true marketing ROI.

How to create UTM links?

You don’t need to manually type out long strings of code. That’s a recipe for typos and broken links. Instead, use the Google Campaign URL Builder. It follows a specific logic: it adds a ? to the end of your URL to designate parameters, uses underscores for the labels (e.g., utm_source=), and uses & to join the different parameters together.
UTM builder from Google

Finding your UTMs in GA4

Once you’ve launched your campaign, you’ll want to see how it’s performing.

In GA4, this data lives in two primary spots under Reports > Acquisition:

User Acquisition: This focuses on how people first found your site. You’ll look for dimensions like “First user source/medium.”

Traffic Acquisition: This focuses on where the current session came from. Here, you’ll look for “Session source/medium.”

These two reports are almost always in the report section, but as you can customise the report section of GA4, you might find that the data is in different places.

A word of caution on the Real-time Report: If you’re testing a link and looking at the “First User” cards, keep in mind that if you’ve visited the site before, that information won’t show up. Use the session-based dimensions instead for a more accurate live view.

Acquisition Reports

You may find that the reports default to the dimensions ‘Primary Channel Group’ but clicking on the drop down opens up a whole host of options, which will help you find your UTMs quicker, particularly the ones that focus on source / medium.

Clicking on the ‘+’ button gives you the opportunity to add an additional dimension – including campaign. All of these you would have built out when building your UTMs

Drop down and + button

Building an exploration

Sometimes the standard reports feel a bit cluttered.

If you want a clean view of your campaign performance, the “Explore” section is your best friend.

  1. Navigate to Explore and select a Blank report.
  2. Add Dimensions: Search for “Session campaign” and “Session source / medium.”
  3. Add Metrics: Choose “Sessions” and “Session key event rate” (this is what GA4 now calls conversion rate).
  4. Drag and drop these into your rows and values.
Explore Report

If you wanted to hone in on a particular campaign you’ve run, you can use the filter option to search for a particular source / medium or campaign, and see the relevant details.

Common Pitfalls to Avoid

Even seasoned marketing managers trip up on these.

Here is how to keep your data clean:

Don’t tag internal links: Never use UTMs for links inside your own website (e.g., a banner on your homepage leading to a product page). Doing so strips away the original attribution data and makes it look like the “source” of the sale was your own homepage.

Shorten URLs AFTER tagging: If you use Bitly or similar tools, attach your UTMs first, then shorten the long link. This will prevent the data going into the direct bucket.

Mind the Redirects: Always test your links. Some website redirects are “greedy” and will strip the UTM parameters off the end of the URL before the page loads.

The PDF “Black Hole”: Direct traffic often comes from non-web documents like PDFs or Word files because they don’t send “referrer” information. By tagging links inside your whitepapers or brochures, you can finally see how much business your offline assets are actually driving.

So there you have it – UTM fun!

My best advice is to ensure you are consistent with UTMs, understand how to view the relevant information. And most importantly, take the information about campaign success (or otherwise) and grow and learn. Hopefully, this blog helps you with that.

Frequently Asked Questions

Why is my email traffic showing as “Unassigned” in GA4?

This usually happens because your UTM parameters don’t match Google’s Default Channel Grouping rules. For example, if you use utm_medium=klaviyo instead of utm_medium=email, GA4 might not know where to put it.

Can I track “Source Platform” or “Creative Format” in GA4?

As of right now, these specific UTM dimensions are not natively reported in the standard GA4 interface, though you can often capture them via custom dimensions if necessary.

Do I need a UTM for every single link?

If it’s an external link you control (Social ads, Email, Guest posts, PDFs), then yes. If you don’t tag it, you’re leaving your attribution to chance.

Kyle

Author

Hello, I'm Kyle Rushton McGregor!

I’m an experienced GA4 Specialist with a demonstrated history of working with Google Tag Manager and Looker Studio. I’m an international speaker who has trained 1000s of people on all things analytics.

Find out more About me
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