What are UTM parameters?
A UTM value is a named URL parameter, such as utm_source=newsletter. Google documents manual campaign tagging for referral and advertising links and shows the resulting values in its Traffic acquisition report. The values describe the link’s campaign labels, rather than a verified account of every interaction in a customer journey. GA4 campaign URL guidance.
The familiar fields and GA4 additions
Source, medium and campaign identify where the link was placed, the marketing medium and the campaign name. Term and content add keyword or creative distinctions. Google recommends including source, medium and campaign when tagging a URL. GA4 also recognizes fields such as campaign ID and source platform; the familiar five are not the entire current list. GA4 campaign URL guidance.
| Field | Documented purpose | Illustrative value |
|---|---|---|
utm_source | Referrer or traffic source | newsletter |
utm_medium | Marketing medium | |
utm_campaign | Campaign name | spring-guide |
utm_term | Paid keyword | garden-tools |
utm_content | Creative or link distinction | header-link |
Build the URL without dropping existing state
Google’s manual format separates the query from the path with a question mark and separates parameter-value pairs with ampersands. Values are case-sensitive. Use a URL builder or URL-aware code so that an existing query string and fragment remain intact. GA4 campaign URL guidance.
This JavaScript builds a hypothetical newsletter link on the reserved example.com domain. The existing view parameter and details fragment are retained. It is sample code, not a published campaign or a link to a page on this site.
const url = new URL("https://example.com/guide/?view=summary#details");
url.searchParams.set("utm_source", "newsletter");
url.searchParams.set("utm_medium", "email");
url.searchParams.set("utm_campaign", "spring-guide");
console.log(url.toString());Read the right GA4 dimension
Google lists Session source/medium, Session source, Session medium and Session campaign in Traffic acquisition. Its documentation also says UTM parameters are omitted from Landing page + query string and Page path + query string, but appear in Page location. That report behavior does not establish that Analytics removes them from the browser address bar. GA4 campaign URL guidance.
Handle duplicate URLs separately from measurement
If a tagged URL serves the same content as the clean URL, canonicalization can express the preferred version. Google documents canonical annotations as signals for duplicate or very similar pages and may choose a canonical itself. A tracking label is not an instruction that guarantees the tagged URL will be excluded from search. Google canonical URL guidance.
Make campaign names consistent
Google recommends consistent, case-sensitive naming across source, medium and campaign. Different capitalization or separators can fragment a campaign into different values. Choose an agreed set of names and keep it with the campaign record so the person building the next link can reuse it. GA4 campaign URL guidance.
Separate external campaign tags from internal events
Use campaign labels for the external placements you want to compare. For a menu click or an in-page button, define an interaction event rather than attaching a new acquisition label. That keeps the question “which placement brought the visit?” separate from “what did the visitor do next?”
GA4 associates events with a session, and the session_start event carries information used for session attribution. Interpret a tagged click alongside the documented session-start rules rather than assuming it represents a separate session. GA4 session documentation.
Verify the complete link path
Open a proposed link and check its destination, query parameters and fragment after any redirects. Confirm that the intended campaign dimensions are collected before using a campaign report for decisions. A copied tagged URL still contains its original labels, so avoid treating a shared link’s tags as proof of the actual person or channel that passed it along.
Questions about UTM Parameters
Which UTM fields should I include?
Google recommends source, medium and campaign, and strongly recommends setting relevant fields consistently. Missing fields can produce not-set values; GA4 supports additional fields beyond the familiar five.
Are UTM values case-sensitive?
Yes. Google treats differently capitalized values as different values. Use a documented naming convention so a single campaign does not split across rows.
Do UTM parameters prove a campaign caused a conversion?
No. They provide campaign labels for collected traffic. Attribution rules and data coverage affect reported credit, while causal questions require separate evidence.
Related terms
Attribution · Google Analytics · Tag Manager · Click-Through Rate