UTM Builder - Free Campaign URL Builder for GA4

What each UTM field is for

UTM tags are plain query parameters. When someone clicks a tagged link, Google Analytics 4 reads them and files the visit under the source, medium, and campaign you chose, instead of guessing. Without them, a click from your email newsletter often shows up as Direct, and you cannot prove the newsletter did anything.

utm_source is who sent the visitor: newsletter, facebook, google, a partner's name. utm_medium is the type of channel: email, cpc, social. utm_campaign is the specific push: fall-sale-2026, product-launch. These three are marked required in the builder, because a link missing any of them produces half-empty reports.

utm_term is optional and traditionally holds the paid keyword. utm_content is optional and separates links that share everything else, like the header button versus the footer link in one email, or two ad creatives in an A/B test. GA4 also recognizes utm_id, a campaign ID used when importing cost data; add it by hand if your ad platform gives you one.

How the builder works

Paste your landing page into the base URL field. If you leave off the scheme, https:// is added for you. Fill in the fields and the tagged link builds as you type. Spaces and special characters are percent-encoded so the link does not break, but hyphens read better in reports: fall-sale-2026 beats fall sale 2026.

The form opens with an example already filled in, so you can see a finished link before touching anything. Replace the values, hit copy, done.

Why lowercase is on by default

GA4 treats UTM values as case-sensitive. utm_source=Facebook and utm_source=facebook become two different rows in your acquisition reports. Over a year, with a few people on the team building links, you end up with Facebook, facebook, FB, and fb, and every chart undercounts your best channel.

The force lowercase option converts everything you type to lowercase before building the link. Leave it on. The only reason to switch it off is if you are matching an existing naming scheme that already uses capitals, and even then it is usually better to fix the scheme.

Worked example: one email, two links

You are sending a fall sale email and want to know whether the hero button or the text link at the bottom pulls more clicks. Base URL: example.com/fall-sale. Source: newsletter. Medium: email. Campaign: fall-sale-2026. Content: hero-button.

The builder returns https://example.com/fall-sale?utm_source=newsletter&utm_medium=email&utm_campaign=fall-sale-2026&utm_content=hero-button. Change content to footer-link for the second link. In GA4, both visits land under the Email channel and the same campaign, and the content dimension splits them so you can see which link won.

Medium values GA4 actually understands

GA4 sorts traffic into default channel groups by matching your source and medium against fixed rules. Use a medium it recognizes and the visit lands in the right bucket automatically. Invent one and it falls into Unassigned, where nobody looks.

The safe list: email for newsletters and transactional mail, cpc for paid search clicks, social for organic posts on social networks, referral for links from other websites, affiliate for affiliate partners, and display for banner ads. Paid social works when the source is a recognized social network and the medium signals paid, such as cpc or paid-social. Google publishes the full rule set in its GA4 default channel group documentation.

Mistakes that wreck attribution

UTMs on internal links. Tagging a banner on your own homepage that points to your own pricing page overrides the visitor's real source. The person who arrived from a Google ad now looks like they came from homepage-banner, and your ad gets no credit. UTMs are for links that point to your site from somewhere else. Period.

Inconsistent names. email in one campaign, e-mail in another, Email in a third. Keep a shared list of approved values and stick to it.

Personal data in tags. Never put an email address or a name in a UTM value. Google Analytics policy prohibits sending personally identifiable information, and URLs end up in logs and screenshots.

Tagging Google Ads links manually when auto-tagging is on. The gclid parameter already handles attribution in GA4, so manual UTMs there are usually redundant, and a mismatched manual tag just muddies the reports.