UTM Parameters (UTM)

UTM parameters are tags added to a link so analytics can tell where each visit came from. Everything after the question mark in this link is UTM data: ?utm_source=facebook&utm_medium=paid_social&utm_campaign=sept_promo

There are five classic parameters. utm_source names the site or platform, like facebook or newsletter. utm_medium names the type of traffic, like email, cpc, or paid_social. utm_campaign names the promotion. utm_content separates variations, like two buttons in one email. utm_term records a paid keyword. GA4 also accepts utm_id and a few newer parameters for platform and creative details.

Naming discipline matters more than the parameters. Values are case sensitive, so Facebook and facebook become two separate sources. Pick lowercase, use underscores instead of spaces, and keep a shared sheet of approved values. GA4 sorts traffic into default channel groups using utm_medium, so nonstandard values like “fb_ads” can land in Unassigned.

Two rules prevent broken reports. Never put UTMs on links between pages of your own site, because the internal tag overwrites the visitor’s real source. And don’t add UTMs to Google Ads links when auto-tagging is on. The gclid parameter that Google Ads adds automatically already passes richer data to GA4.