Free tool · UTM link checker for GA4
Free UTM checker for GA4
A UTM checker reads tagged links and flags the mistakes that split or lose campaign data in Google Analytics 4. Paste your links, one per line, and this free UTM checker shows the GA4 channel each link is expected to land in, every tag that breaks a naming rule, and names that don't match across the list, with a fixed link for each.
By the Dolphin Analytics team · Last updated · Channel rules checked against Google's GA4 default channel group
utm_source is spelt 3 ways: "Facebook", "facebook", "fb". GA4 shows each spelling as a separate value. Pick one, such as facebook, and use it on every link.
utm_campaign is spelt 2 ways: "Spring Sale", "spring_sale". GA4 shows each spelling as a separate value. Pick one, such as spring_sale, and use it on every link.
- Facebook / paid social
https://example.com/sale?utm_source=Facebook&utm_medium=paid social&utm_campaign=Spring SaleExpected GA4 channel: Paid Social- FIXCapital letters. GA4 counts "Facebook" and "facebook" as two sources. The fixed link uses lowercase.
- FIXSpaces in a tag. The fixed link uses underscores, so the link never breaks when pasted.
Fixed linkhttps://example.com/sale?utm_source=facebook&utm_medium=paid_social&utm_campaign=spring_sale - facebook / email
https://example.com/sale?utm_source=facebook&utm_medium=email&utm_campaign=spring_saleExpected GA4 channel: Organic Social- CHECKfacebook with an email medium doesn't look right. If the link sits in an email, set source to your list or email tool (for example newsletter). If it's a facebook ad or post, change the medium. The fixed link uses paid_social. If that's wrong for this link, use social instead.
Fixed linkhttps://example.com/sale?utm_source=facebook&utm_medium=paid_social&utm_campaign=spring_saleExpected GA4 channel after the fix: Paid Social - fb / facebook
https://example.com/sale?utm_source=fb&utm_medium=facebook&utm_campaign=spring_saleExpected GA4 channel: Organic Social- CHECK"facebook" is a site name, not a type of traffic, so GA4 can miss paid clicks or put them in Unassigned. Put the site in source and the type of traffic in medium. The fixed link uses paid_social. If that's wrong for this link, use social instead.
Fixed linkhttps://example.com/sale?utm_source=fb&utm_medium=paid_social&utm_campaign=spring_saleExpected GA4 channel after the fix: Paid Social - newsletter / email
https://example.com/sale#utm_source=newsletter&utm_medium=email&utm_campaign=spring_saleExpected GA4 channel: Email- CHECKThe tags sit after the #. Google's instructions put UTM tags after a ?, before any #, so GA4 may not read them here. The fixed link moves them.
Fixed linkhttps://example.com/sale?utm_source=newsletter&utm_medium=email&utm_campaign=spring_sale
Runs in your browser. Nothing you paste is sent to Dolphin Analytics.
What does the UTM checker look for?
The UTM checker tests each link against the naming rules GA4 relies on and Google's published channel rules. It looks at one link at a time, then compares the whole list, because a campaign split across "Facebook" and "facebook" only shows up when you see both.
| Check | What goes wrong in GA4 |
|---|---|
| Source or medium missing | Visits can't be put in the right channel |
| Campaign missing | Visits have no campaign name |
| Capital letters or spaces | One campaign shows as several rows |
| A medium GA4 doesn't recognise | Visits land in Unassigned |
| A site name as the medium, such as facebook | Paid clicks are counted as unpaid, or land in Unassigned |
| Source and medium that don't fit, such as facebook with email | Visits land in the wrong channel |
| Tags after the # in the address | GA4 may not read them |
| The same tag twice in one link | No way to be sure which value GA4 reads |
| An ad click ID copied into the link | Every visit carries one old click's ID |
| One name spelt several ways across the list | One platform or campaign reports as two or three |
Why is my campaign traffic in Unassigned?
GA4 puts a visit in Unassigned when its source and medium match none of Google's default channel rules. One cause is a medium GA4 doesn't know, such as utm_medium=newsletter_blast. The checker names the rule each link fails and writes a fixed link with a medium that lands in a real channel.
Where should UTM tags go in a link?
UTM tags go after a question mark, joined by ampersands, as in example.com/page?utm_source=newsletter&utm_medium=email. That is the format in Google's URL builder help. Tags placed after a # are part of the page fragment, which Google's instructions don't use, so the checker moves them before the #.
Frequently asked questions
Is this UTM checker free?
Yes. The Dolphin Analytics UTM checker is free, needs no sign-up and runs in your browser, so the links you paste are never sent to us.
How many links can I check at once?
Up to 500 at a time, one per line. The checker also compares the whole list, so names spelt differently on different links show up.
Does the UTM checker test whether the page loads?
No. It checks the tags in the link, not the page behind it. A page that redirects can drop the tags, so open one fixed link in a private window and check it shows in GA4's Realtime report.
Is the expected channel always what GA4 shows?
It follows Google's published default channel group rules. Google matches sources against its own full lists of search, social, video and shopping sites, so a rare source can land in a different channel. Custom channel groups in your property also change the result.
How do I build a new tagged link?
Use the free UTM builder. It applies the same rules as you type, so new links pass this checker first time.
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