The Complete UTM Parameters Glossary (Every Term Explained)

utm_source

utm_source identifies the specific platform or publisher that sent the traffic, such as newsletter, facebook, or a partner site's domain name. It answers the question of where the click physically originated. This is typically the broadest and most consistently used of the five standard UTM parameters, and it is usually the first field reported on in any campaign dashboard.

Common mistakes involve inconsistent casing or naming across campaigns, such as mixing Newsletter, newsletter, and email_newsletter for the same channel. For a full breakdown of how source relates to the other core parameters, see UTM source vs UTM medium vs UTM campaign.

utm_medium

utm_medium describes the general category of channel the traffic came through, such as email, cpc, social, or referral. Where utm_source names the specific publisher, utm_medium groups that publisher into a broader bucket that lets you compare, for example, all paid channels against all organic channels regardless of which specific platform sent the click.

Analytics platforms like Google Analytics 4 use medium as one of the primary dimensions for grouping default channel reports, so consistency in this field directly affects how cleanly your traffic rolls up into standard reporting views.

utm_campaign

utm_campaign names the specific marketing initiative the link belongs to, such as summer_sale_2026 or product_launch_q3. This is the parameter that ties together every channel and creative variant participating in one coordinated push, letting you measure total campaign performance across email, paid social, and organic posts as a single unit even though each individual link carries a different source and medium.

Because campaign names are freeform text, they are the parameter most prone to drift without a shared naming convention. A team without an agreed format will end up with summer-sale, SummerSale2026, and summer_sale_26 all referring to the same initiative, fragmenting the data across three buckets instead of one.

utm_term

utm_term was originally designed to capture the paid search keyword that triggered an ad click, and it still serves that purpose in many search campaigns. Outside of paid search, some teams repurpose it to capture audience segment or targeting detail, though this is a looser convention than the search keyword use case it was built for.

Because most modern paid search platforms can auto-populate this field through dynamic parameter insertion, manual use of utm_term has become less common than it once was, but it remains useful whenever a team wants to distinguish performance by keyword or audience within a single ad set.

utm_content

utm_content differentiates between multiple versions of the same ad, email, or link that otherwise share identical source, medium, and campaign values. It is the parameter of choice for A/B testing creative, distinguishing a header link from a footer link in the same email, or separating two different ad images running in the same campaign.

For a deeper comparison of when to reach for utm_term versus utm_content, and how they are frequently confused, see UTM term and UTM content explained.

gclid

gclid, short for Google Click Identifier, is a unique parameter Google Ads automatically appends to a destination URL when someone clicks a Google Ads listing, assuming auto-tagging is enabled on the account. Unlike the five UTM parameters, gclid is not something a marketer manually sets, it is generated per click and used by Google Analytics and other systems to import cost and conversion data tied to that specific ad interaction.

gclid can appear alongside UTM parameters on the same URL, and the two are not mutually exclusive, though some accounts rely on gclid alone for Google Ads attribution rather than manually building UTM tags for every ad.

fbclid

fbclid, or Facebook Click Identifier, works similarly to gclid but is appended by Meta's advertising and organic sharing systems when a link is clicked from Facebook or Instagram. It allows Meta's own reporting tools to tie a click back to a specific ad or post. Like gclid, it is generated automatically rather than manually configured by the marketer.

A frequent point of confusion is that fbclid can sometimes appear on links even when no UTM parameters were manually added, since Meta's platform-level tracking is independent of whether a marketer built the link with a UTM tool.

msclkid

msclkid is the Microsoft equivalent of gclid, automatically appended by Microsoft Advertising (the platform behind Bing Ads) to track ad clicks originating from its network. It serves the same functional purpose: connecting a click event to Microsoft's own ad reporting and conversion data, independent of any manually applied UTM tags.

Teams running search campaigns across both Google and Microsoft Advertising will often see gclid and msclkid appear on different portions of their traffic depending on which network the click came from, alongside whatever UTM parameters were manually configured on the ad's destination URL.

Click ID (General Term)

Click ID is the general category name for any of the auto-generated identifiers described above, gclid, fbclid, msclkid, and similar parameters used by other ad platforms. These identifiers are typically long alphanumeric strings, unlike the human-readable values marketers choose for UTM parameters, and they exist primarily to feed each platform's own conversion tracking and reporting systems rather than to be read or interpreted by a person.

Click IDs and UTM parameters solve related but distinct problems: click IDs feed the ad platform's own closed reporting loop, while UTM parameters feed your own analytics platform's view of traffic regardless of which ad platform sent it.

UTM Link (Or Tagged Link)

A UTM link, sometimes called a tagged link, is simply any URL that has one or more UTM parameters appended to its query string. It is not a separate technology from a normal URL, it is the same destination address with extra information attached after a question mark so analytics platforms can identify where the visit came from.

For the foundational explanation of how these links are built and why they matter, start with the complete guide to UTM parameters.

Query String

The query string is the portion of a URL that comes after the question mark, made up of one or more key-value pairs separated by ampersands. UTM parameters live inside the query string alongside any other parameters a site might use, such as session identifiers or product filters. Understanding the query string structure helps explain why UTM parameters do not change what page loads, they only pass along extra information the destination page's analytics script can read.