Free tool · UTM builder with smart checks
Free UTM builder for GA4
A UTM builder adds tracking tags to a link so Google Analytics 4 knows which campaign sent each visitor. A basic builder joins whatever you type into a URL. This one also runs smart checks on every link: it flags a source and medium that don't fit together, such as facebook with email, offers a one-click fix, and shows which GA4 channel the visit will land in before you publish. It keeps every value lowercase, builds links one at a time or in bulk, and ends with next steps for testing the link.
By the Dolphin Analytics team · Last updated · Channel rules checked against Google's GA4 default channel group
https://example.com/spring-sale?utm_source=facebook&utm_medium=paid_social&utm_campaign=spring_sale&utm_content=video_a - FIXED Capital letters made lowercase. GA4 counts "Facebook" and "facebook" as two sources.
- FIXED Spaces replaced with underscores, so the link never breaks when pasted.
- Open the link in a private window, then check the visit shows in GA4's Realtime report with this source and medium.
- In Meta Ads Manager, paste the tags (everything after the ?) into the ad's URL parameters box, and the page address into the website URL box.
- Note the campaign name and reuse it exactly on every link in this campaign, so GA4 shows one row, not several.
Runs in your browser. Nothing you type is sent to Dolphin Analytics.
What are UTM parameters?
UTM parameters are five tags added to the end of a link (source, medium, campaign, term and content) that tell Google Analytics 4 where a visit came from. GA4 needs source and medium to sort the visit into a channel; campaign groups visits from one push, and term and content tell ads or creatives apart.
| Tag | What it records | Example |
|---|---|---|
| utm_source | The site or platform that sent the visit | |
| utm_medium | The type of traffic | paid_social |
| utm_campaign | The campaign or promotion | spring_sale |
| utm_term | The paid keyword or audience | lookalike_audience |
| utm_content | The ad, creative or link position | video_a |
What do the smart checks catch?
Most broken UTM links are typed correctly but tagged wrongly: the URL works, yet GA4 files the visits in the wrong channel or splits one campaign into several rows. The smart checks read the source, medium and campaign name together, against Google's GA4 default channel rules, and warn you while you can still change the link.
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A source and medium that don't fit
facebook with medium email, a search engine with a social medium, or an email list with a medium that isn't email. Each warning says what GA4 will do with the visits and offers a suggested fix you can apply in one click.
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A site name as the medium
utm_medium=facebook or utm_medium=linkedin names a platform, not a type of traffic, so paid clicks can be counted as unpaid or land in Unassigned.
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Paid clicks GA4 counts as unpaid
A medium such as ads or sponsored reads as paid, but GA4 only treats a medium as paid when it contains cp (such as cpc or cpm), is ppc or retargeting, or starts with paid.
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Campaign names that change the channel
GA4 reads some words in the campaign name, such as shop or cross-network, and moves the visits to a different channel. The check names the word so you can take it out.
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Capitals, spaces and missing tags
Values are made lowercase, spaces become underscores, and you're told if source, medium or campaign name is missing.
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Next steps for the link
After the checks, the builder lists what to do next: test the link in GA4 Realtime, use auto-tagging for Google Ads, or paste the tags into Meta's URL parameters box.
Which GA4 channel will my link land in?
GA4 picks the channel from the source and medium using Google's published default channel group rules. A paid medium such as cpc, ppc or anything starting with "paid" plus a social source gives Paid Social; email as the medium gives Email; a medium GA4 does not recognise gives Unassigned. The builder above applies the same rules, in the same order. GA4 matches sources against Google's own source lists, so a rare source can land differently from the prediction.
What are the most common UTM mistakes?
Three mistakes cause most of the messy campaign rows in GA4 reports.
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Mixed capitals
GA4 stores "Facebook" and "facebook" as two different sources, so one campaign splits into two rows.
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A platform name as the medium
utm_medium=facebook matches no paid channel rule, so paid clicks are counted as organic social or land in Unassigned.
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Tags on internal links
UTMs on links between your own pages overwrite the real source of the visit. Use them on links that point to your site from somewhere else.
Frequently asked questions
Is this UTM builder free?
Yes. The Dolphin Analytics UTM builder is free, needs no sign-up and has no limit on links. It runs in your browser, so the links you build are never sent to us.
How is this UTM builder different from other UTM builders?
It checks the link as well as building it. The smart checks flag a source and medium that don't fit together, a site name used as the medium, paid clicks GA4 would count as unpaid and campaign names that change the channel, then offer a one-click fix and show the GA4 channel the visit will land in.
Should UTM parameters be lowercase?
Yes. GA4 treats capital and lowercase letters as different values, so "Email" and "email" show as two sources. Keeping every UTM value lowercase stops one campaign splitting across rows.
Why is my UTM traffic showing as Unassigned in GA4?
GA4 puts a visit in Unassigned when its source and medium match none of the default channel rules, often because the medium is a made-up label such as "banner_ad" or "promo". Use a recognised medium such as cpc, paid_social, email or referral.
What medium should I use for Facebook ads?
Use source facebook (or instagram) with medium paid_social or cpc. GA4 counts a social source with a paid medium as Paid Social. Putting facebook in the medium box, or using a medium such as facebook_ads, makes GA4 count the clicks as unpaid traffic.
Do I need UTMs on Google Ads links?
Usually not. With auto-tagging on, Google Ads adds a gclid to each click and GA4 reads the campaign from it. Manual UTMs are for platforms without that link, such as Meta, LinkedIn, email and offline.
Can I build UTM links in bulk?
Yes. Switch to Bulk, paste one page address per line, and the builder adds the same tags to every link.
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