UTM in Google Analytics 4
Google Analytics 4 reads the standard utm_ query parameters and maps them to its session and traffic-source dimensions. The mapping is specific: utm_source, utm_medium, and utm_campaign feed the core dimensions, utm_id powers the manual campaign ID, and utm_source/medium combinations drive GA4's default channel grouping. Knowing the exact mapping prevents tags that look fine but land in the wrong channel.
How GA4 maps the parameters
GA4 maps utm_source to Session source, utm_medium to Session medium, utm_campaign to Session campaign, utm_content to the manual ad content dimension, and utm_term to the manual keyword. utm_id sets the manual Campaign ID, which GA4 uses to join campaign cost data.
GA4 also recognises the newer utm_source_platform, utm_creative_format, and utm_marketing_tactic parameters, mapping them to their own manual dimensions.
- utm_source → Session source
- utm_medium → Session medium
- utm_campaign → Session campaign; utm_id → Campaign ID
- utm_content/utm_term → manual content/keyword
Channel grouping depends on medium
GA4's default channel grouping classifies a session largely from utm_medium (and sometimes source). For example a medium of email, affiliate, or organic-social style values routes to the expected channel, while an unrecognised medium can land in Unassigned.
If a campaign shows in the wrong channel, check utm_medium against GA4's documented channel-grouping rules before assuming a tracking bug.
How it appears in analytics and logs
In GA4, a UTM-tagged landing hit sets the session's source, medium, and campaign from the matching utm_ parameters. If a campaign appears under Unassigned or the wrong channel, it usually means the utm_medium did not match the value GA4's channel grouping expects.
Diagnostic use case
Tag links so they populate the right GA4 dimensions and channel grouping, and debug why a campaign shows up under an unexpected channel in GA4 reports.
What WebmasterID can help detect
WebmasterID reads the same UTM parameters server-side and can corroborate what GA4 attributes, so you can cross-check a campaign's source/medium without depending solely on client-side tags that ad blockers may drop.
Common mistakes
- Putting a campaign name in utm_medium, which then misroutes channel grouping.
- Expecting utm_id to replace utm_campaign — it complements it for cost joins.
- Assuming any medium value maps cleanly; unknown mediums fall to Unassigned.
- Relying only on client GA4 tags that blockers drop, with no server-side check.
Privacy and accuracy notes
GA4 stores the campaign dimensions, which describe the link, not the person. UTMs do not add personal data; GA4's own consent and data-handling controls govern the visitor side independently of the UTM.
Related pages
- UTM parameters and default channel grouping
Analytics tools sort traffic into channel groups (Paid Search, Organic Social, Email, Referral, Other) using rules built mostly on utm_medium. Choose the wrong medium and good traffic falls into 'Other' or the wrong channel. This page explains how the mapping works and the medium values that keep channels correct.
- utm_id and campaign IDs
utm_id is a campaign-identifier parameter that analytics tools use to join UTM-tagged sessions with imported cost or campaign metadata. It is not a replacement for utm_campaign's human-readable name. This page explains what utm_id does, when to use it, and how it relates to the other parameters.
- UTM tracking in Plausible Analytics
Plausible is a privacy-first, cookieless analytics tool that reads the standard utm_ parameters and exposes them as Source, UTM Medium, UTM Campaign, UTM Content, and UTM Term properties. Because Plausible avoids cookies and cross-site identifiers, UTMs are the primary way to attribute campaigns. This page covers how Plausible consumes the parameters and groups acquisition sources.
- Attribution analytics
Corroborate GA4 campaign attribution from server-side data.
Sources and verification notes
- Google Analytics Help — Collect campaign data with custom URLsOfficial utm_ parameter list and the GA4 dimensions they map to.
- Google Analytics Help — Default channel groupHow utm_medium/source drive GA4 channel grouping.
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.