A UTM parameter is an addition to a URL that records where a visitor came from. You add the parameters after the address, following a question mark. Google Analytics 4 reads them and shows them in its traffic source reports. Google advises always using three parameters: utm_source, utm_medium and utm_campaign.
The main parameters
| Parameter | What it indicates | Example |
|---|---|---|
utm_source | The source | newsletter |
utm_medium | The medium | email |
utm_campaign | The campaign | spring-sale |
utm_content | Which link or variant | top-button |
utm_term | The paid keyword | city-bike |
Google also recommends utm_id and utm_source_platform.
Example
https://www.example.com/offer?utm_source=newsletter&utm_medium=email&utm_campaign=spring-saleAnyone who clicks this link in the newsletter shows up in GA4 with source newsletter and medium email.
Common mistake
Inconsistent spelling. According to Google, the values are case sensitive: Newsletter and newsletter count as two sources. Agree on a spelling in advance. If a parameter is missing, the reports show (not set).
How to group sources in GA4, including traffic from AI assistants, is covered in Tracking traffic from ChatGPT and other AI assistants in Google Analytics 4.