What is UTM Parameters?
Short text codes added to URLs that tell GA4 exactly where traffic came from (Source, Medium, Campaign).
UTM stands for "Urchin Tracking Module" (a callback to the software Google bought to create Google Analytics natively). They are the backbone of digital marketing attribution.
Without UTMs, GA4 has to guess where traffic came from by looking at the HTTP Referrer. If a user clicks a link in an email client or a native social media app, there is no referrer, and GA4 categorizes the traffic as "Direct" (unknown).
The Core 3 Parameters:
- utm_source: The specific site or platform sending you traffic (e.g.,
facebook,newsletter,google). - utm_medium: The overarching channel category (e.g.,
cpc,email,social). - utm_campaign: The specific promotion or product launch (e.g.,
summer_sale_2026).
Example: url.com?utm_source=facebook&utm_medium=cpc&utm_campaign=retargeting
You can easily generate and validate these links using our free UTM Builder.
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Related terms.
Traffic where GA4 cannot determine the source or medium because the UTM parameters or referrer data do not match any known Default Channel Grouping.
Traffic categorized as Direct when a user types your URL directly into their browser, uses a bookmark, or when GA4 entirely loses the referral data (Dark Social).
Rule-based groupings of traffic sources that roll up granular UTM data into high-level categories (e.g., 'Organic Search', 'Paid Social').