What Are UTMs and Why Do They Matter?
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If you’ve ever clicked on a link and noticed a long string of extra text at the end of the URL looking something like:
?utm_source=facebook&utm_medium=paid_social&utm_campaign=spring_sale, you’ve seen a UTM in action.
UTM stands for Urchin Tracking Module, and it’s simply a way to tag your links so tools like Google Analytics 4 (GA4) know exactly where your visitors came from. They’re not scary, and you don’t need to be a developer to use them.
Here’s why they matter: without UTMs, GA4 often has to guess where your traffic is coming from, and those guesses aren’t always right. That can lead to paid ad clicks showing up as organic traffic, email campaigns being counted as “direct,” or whole marketing channels being misclassified.
When your UTMs are consistent and accurate, your reporting becomes crystal clear. You’ll be able to see which campaigns are working, which ones need improvement, and where to focus your marketing budget for the biggest impact.
In this post, I’ll walk you through why accurate tracking matters, how UTMs fit into the picture, common mistakes I see, and a few tips for keeping your data clean. I’ll also share a GA4 report you can use right now to get a better view of your traffic sources.
Why UTMs Are Important for GA4 Reporting
If you are running paid ads, email campaigns, or even just trying to measure how well your organic traffic is performing, your Google Analytics 4 (GA4) setup needs to be rock solid.
The challenge? Even the smallest tracking mistake in traffic-source dimensions can throw your numbers off and lead you to make decisions based on faulty information. That can mean wasted budget, missed opportunities, and a lot of unnecessary frustration.
GA4: Your Marketing Compass
Think of GA4 as your compass. It helps you understand where your traffic is coming from and how visitors are engaging with your site. When it’s set up and maintained correctly, GA4 can tell you which campaigns are worth scaling, which ones need adjustments, and which channels are falling flat.
Regularly reviewing your GA4 data is one of the most important habits you can build. Doing so helps you:
Catch mistakes in ad setups before they get costly
Identify bogus bot traffic that can skew your results
Spot referral traffic you didn’t know was there
See which marketing channels are really pulling their weight
But here’s the catch: GA4’s accuracy depends entirely on the information you give it. And that’s where UTMs come in.
UTMs: The Road Signs for Your Campaigns
UTM parameters are bits of text you attach to a link so GA4 knows exactly where that click came from. Without UTMs, or with UTMs that are incorrect, your reporting can quickly get messy.
Example: If a paid ad has a misaligned UTM, GA4 might count that visit as organic instead of paid. That makes it look like your organic traffic is growing, when really your ads are doing the heavy lifting.
I see UTM mistakes in client accounts more often than not. And even a single error can cause weeks or months of misleading reporting.
The 5 UTM Fields I Always Check
Here’s what each one means and how it shows up in GA4:
Source: Where the traffic came from.
Example: google, facebook, newsletter
In GA4: Appears as Session source in traffic reports.
Medium: The type of traffic.
Example: cpc for paid ads, email, organic, social
In GA4: Appears as Session medium so you can compare channels.
Campaign: The name of your campaign.
Example: spring_sale, product_launch, brand_awareness
In GA4: Lets you see performance at the campaign level.
Content: The specific version of an ad or link.
Example: blue_banner, video_a, cta_top
In GA4: Useful for A/B testing creative variations.
Placement: Where the ad appeared.
Example: sidebar, instagram_feed, homepage_banner
In GA4: Helps pinpoint which placements convert best.
Use Terms GA4 Will Recognize
Even if you fill out every UTM field, your tracking can still go sideways if you use terms GA4 doesn’t understand. GA4 will try to classify traffic based on its own rules. If your term doesn’t match what it expects, that traffic can end up misclassified under a default source, “unassigned,” or “not set.”
For example, if you set your medium as “meta_ad” instead of the recognized term “paid”, GA4 may log that traffic as organic social instead of paid social. That means your paid campaign’s results could be hiding inside your organic reports, giving you the wrong picture of what’s working.
The safest approach is to stick to standard naming conventions for your UTMs, especially for source and medium. Platforms like Google, Facebook, and LinkedIn already have well-known formats for these fields. Using the recognized terms keeps your GA4 reports accurate and easy to interpret.
Here’s a list of acceptable terms to use aligning with the default channel group in GA4.
How to Create a UTM
The good news is, you don’t have to be a coder to create a UTM. You can build them manually, or you can use a free tool to make the process faster and reduce the risk of typos. If the platform you’re using has a builder (like Meta or Google ads), use it. It will help ensure consistency and accurate reporting.
Google offers a free campaign URL builder that lets you enter your link, choose your parameters, and generate a properly formatted URL.
If you want to write one manually, just start with your base link and add a question mark (?), followed by each UTM parameter, separated by ampersands (&). For example:
https://www.example.com/product-page?utm_source=meta&utm_medium=paid_social&utm_campaign=spring_sale&utm_content=blue_banner&utm_placement=instagram_feed
When someone clicks that link, GA4 will record the visit as coming from Facebook paid social, under your Spring Sale campaign, with the blue banner creative, placed in the Instagram feed.
You can also use dynamic fields in ad platforms, like {campaign.name} or {adset.name}, so UTMs automatically pull in the correct campaign, ad set, or creative names without having to manually change them for every link.
Precautions When Using Dynamic Fields
Dynamic fields can save time by automatically pulling in campaign, ad set, or creative names into your UTMs, but they can also create messy data if you are not careful.
Inconsistent naming – If your campaign or ad set names are not standardized, the dynamic field will pull them in exactly as written. Even small differences like “SpringSale” vs. “spring_sale” will show up as two separate entries in GA4.
Special characters – Certain characters (like &, ?, %, or spaces) in campaign names can break your UTMs or make them hard to read in reports. Stick to lowercase letters, numbers, and underscores.
Platform-specific rules – Meta, Google Ads, and other platforms have different naming conventions and placeholder formats (e.g., {campaign.name} vs. {campaignid}). Make sure you are using the correct format for each platform.
Testing before launch – Always click a preview of your ad to check that the generated URL contains the correct UTM structure. A quick test can save weeks of bad data.
Dynamic fields are powerful, but like any automation, they work best when paired with clear naming rules and regular audits in GA4.
The key is consistency. Use the same naming conventions across all campaigns so your reports stay clean and easy to read.
UTM Tips for Paid Ads and Email Campaigns
For Paid Ads:
Always use lowercase for UTMs to keep reporting consistent (cpc not CPC).
Use the ad platform’s built-in tracking template where possible. This reduces the risk of typos.
Differentiate between campaigns targeting different audiences, even if the creative is the same.
For Email Marketing:
Use source=newsletter (or email platform name: e.g., Klaviyo) and medium=email for all email sends.
Label the campaign field with a specific send date or theme (e.g., spring_promo_march15).
Use content to test link placement within the email, like cta_top vs. cta_bottom.
How to Pull a Useful GA4 Report on Traffic Sources
One of the simplest and most telling reports you can run in GA4 is the Session source/medium report.
Here’s how to find it:
Go to Reports in GA4.
Click Acquisition > Traffic acquisition.
In the primary dimension dropdown, select Session source/medium.
This will show you exactly where your traffic is coming from and how each source/medium combination is performing in terms of engagement, conversions, and revenue.
From here, you can:
Spot campaigns that are mislabeled as organic
Identify underperforming channels to adjust or cut
See which paid campaigns are producing the highest ROI
The Takeaway
UTMs might seem small, but they can make or break your ability to trust your GA4 data. When they’re clean and consistent, you’ll have a reliable compass guiding your marketing decisions.
Set a reminder to audit your GA4 traffic sources every month, especially after launching new campaigns. If something looks off, question it. Because in marketing, bad data doesn’t just cause confusion—it costs real money.
Need a little support with your reporting game? Let’s connect. I’m a data nerd and love talking analytics!
