UTM Builder

How to use UTM Builder

1. Choose a Mode: Single URL for one link, or Bulk to tag a list of base URLs (one per line) with the same campaign.
2. Enter the Website URL (or the Base URLs). Optionally fill in Your site’s domain so links to your own site are flagged.
3. Fill in the Campaign fields: Source, Medium and Campaign are required, Term and Content are optional. Pick a Preset to fill in a common source and medium, or click Show more fields for the GA4 parameters utm_id, utm_source_platform, utm_creative_format and utm_marketing_tactic.
4. Set the formatting: Lowercase values and how Spaces are written (-, _ or %20).
5. Copy the Tagged URL (or Copy all in bulk mode), or use Send to…. Copied links, and links you Save, appear in History.

How it works

The base URL is parsed with the browser’s URL API. If it has no scheme, https:// is added; anything other than http or https, or a host without a dot (except localhost), is rejected.

Each value is trimmed, optionally lower-cased, and runs of whitespace are replaced with -, _ or a single space depending on the Spaces setting. The non-empty values are then appended in a fixed order (utm_source, utm_medium, utm_campaign, utm_term, utm_content, then the GA4 fields) and encoded with encodeURIComponent, so a space becomes %20. Existing query parameters are kept exactly as written, except UTM parameters you are setting, which are replaced instead of duplicated. The #fragment stays at the end.

Warnings appear for a missing required field, values that mix upper and lower case (analytics tools treat Email and email as different), a scheme that was added, replaced UTM parameters, and links whose host matches your site’s domain or one of its subdomains, because UTM tags on internal links start a new session and overwrite the original traffic source.

Limits

• Only http and https URLs are accepted, and a URL can’t contain spaces.
• A link is still built when a required field is missing; it gets a warning instead of being blocked.
• History keeps the 50 most recent links, without duplicates.
• Presets only fill in source and medium. They follow common conventions; check them against the channel definitions your analytics tool uses.
• The tool builds links only. It can’t check that the destination page exists or that your analytics records the visit.

Privacy

Links are built entirely in your browser, and the site’s Content Security Policy blocks requests to other servers. Links you copy or Save are kept in this browser’s local storage under History, never uploaded; click Clear history to delete them. Nothing else is stored, and there is no share link. If you use Send to…, the link is handed over through this tab’s session storage and removed as soon as the receiving tool reads it.

Frequently asked questions

Which UTM parameters are required?

utm_source, utm_medium and utm_campaign. Without them, analytics tools may file the visit under the wrong channel or campaign. utm_term and utm_content are optional, and the GA4 fields are only needed if you use them in reports or data import.

Should I add UTM tags to links within my own site?

No. A UTM-tagged click starts a new session in analytics, which replaces the visitor’s real source (such as search or email). Enter Your site’s domain and the tool warns when a link points to it.

Why are my values lower-cased?

Because Lowercase values is on by default. Analytics tools treat Facebook and facebook as different sources, so consistent lower case keeps reports clean. Untick it to keep your capitalisation; a warning then flags mixed case.

What happens to UTM parameters already in the URL?

A UTM parameter you fill in replaces the one in the URL, and a warning says so. UTM parameters you leave empty and all other parameters stay as they were.

Do I need UTM tags for Google Ads?

Often not. Google Ads auto-tagging adds a gclid that Google Analytics uses, which usually makes manual UTM tags unnecessary there. The Google Ads preset shows this note.