UTM URL builder

UTM parameters are tags you add to the end of a link to tell Google Analytics where each visit came from. There are five in total: utm_source, utm_medium, utm_campaign, utm_term and utm_content. When someone clicks, Google Analytics reads those values and attributes the visit to the right channel and campaign. Without UTMs, much of your campaign traffic lands in the “direct” bucket and you lose track of what actually drives results.

What each UTM parameter is for

In practice, three parameters cover most campaigns: source, medium and campaign. The other two, term and content, are optional and exist to detail paid search ads and tell apart versions of the same link. The table below sums up the role of each one.

Source vs medium: the most common mix-up

The most frequent question is the difference between source and medium. The source answers “where from”, meaning the specific site or service, like google, facebook or weekly-newsletter. The medium answers “how”, meaning the type of channel, like cpc, email, social or referral. A simple rule: the medium is a short, standardized category, and the source is the exact name of the origin within that category.

Best practices for naming your UTMs

• Always use lowercase. URLs are case sensitive, so “Google” and “google” become two separate sources in your reports.
• Never use spaces. Replace them with a hyphen or underscore (black-friday, not “black friday”), because a space turns into %20 and dirties the data.
• Standardize your names. Define a fixed list of values for source and medium and always reuse the same ones; a single variation splits one campaign into two rows.
• No accents or special characters. They get encoded in the URL and mess up your reports.
• Do not use UTMs on internal links. Tagging links between pages of your own site restarts the session and erases the real origin of the visit.
• Focus on the basics. Source, medium and campaign cover most cases; term and content are for specific situations.

How UTMs show up in Google Analytics

In Google Analytics 4, UTM parameters feed the source and medium dimensions. utm_source becomes the “Session source”, utm_medium becomes the “Session medium” and utm_campaign becomes the “Session campaign”, all under Acquisition, in Traffic acquisition. This is exactly why UTMs should never go on internal links: clicking a tagged internal link makes GA4 open a new session and overwrite the original source, crediting the conversion to the wrong place.

UTM examples by channel

Each channel calls for its own source and medium combination. The examples below show the typical tagging for email, social media and paid ads, and how each one appears in your GA4 reports.