UTM Builder for GA4
Build tracking URLs that GA4 reads correctly the first time — the right source, the right medium, and a campaign name that survives your reports.
Assembled tracking URL
GA4 tracking best practices
GA4 only needs a source to attribute a session, but a missing or invented medium is the single most common reason paid traffic shows up as Unassigned. Fill all three before the link goes out.
| Parameter | Recommended value | Use case |
|---|---|---|
| utm_source | [required] | The only parameter GA4 strictly requires to attribute a session. |
| utm_medium | cpc / email / paid_social | Decides which default channel group the session falls into. |
| utm_campaign | [campaign name] | Groups every link of one initiative into a single report row. |
GA4 UTM FAQs
Only the source is strictly required for GA4 to attribute a session, but in practice you want the medium too: without it the session cannot be mapped to a default channel group and is reported as Unassigned.
Under Reports, then Acquisition, then Traffic acquisition. Switch the dimension to Session source / medium or Session campaign to see the exact values you sent in the link.
Almost always because the medium is a value GA4 does not recognise. Use cpc, email, paid_social, referral, affiliate or organic rather than inventing names such as facebook_ad.
The rest of the UTM toolkit
UTM Checker
Paste a finished campaign URL and see every tag parsed, plus the casing and spacing problems that quietly split your reports.
Bulk UTM Generator
Tag a whole list of destination URLs with one shared campaign, then copy them all or download the result as a CSV file.
What are UTM parameters?
The reference page: what each of the five tags means, the naming conventions that keep GA4 clean, and the mistakes to avoid.