UTM Source vs Medium vs Campaign Explained (With Examples)

UTM source, medium, and campaign answer three different questions: source names where the traffic came from (google, newsletter), medium names how it arrived (organic, cpc, email), and campaign names the specific promotion (spring_sale). A complete tag looks like utm_source=newsletter&utm_medium=email&utm_campaign=spring_sale. Build clean tags instantly with our free UTM Builder, then read on for the naming rules that keep your reports readable.

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What Source, Medium, and Campaign Each Mean

Source, medium, and campaign are three separate dimensions, and confusing any two is the most common UTM mistake. Source answers 'where did this visit come from?' — the specific site, app, or sender: google, facebook, newsletter, youtube, partner_blog. Medium answers 'how did it arrive?' — the channel type: organic, cpc, email, social, referral, video. Campaign answers 'which promotion was it part of?' — the named effort: spring_sale, product_launch, black_friday, webinar_may. A single link carries all three at once: a link in your May newsletter promoting the spring sale is utm_source=newsletter, utm_medium=email, utm_campaign=spring_sale, while a paid Google ad for the same sale is utm_source=google, utm_medium=cpc, utm_campaign=spring_sale. Same campaign, different source and medium, and that separation is the whole point: it lets you compare the same promotion across channels. For the full tagging walkthrough, see our guide on how to build UTM links for marketing campaigns, and build your own with our free UTM Builder.

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UTM Source, Medium, and Campaign Examples by Channel

Examples make the three parameters click faster than definitions. Email newsletter: source newsletter, medium email, campaign spring_sale. Paid Google search: source google, medium cpc, campaign spring_sale. Organic Google search needs no UTM at all — Google Analytics detects it automatically, and tagging it only pollutes the organic channel. Facebook post: source facebook, medium social, campaign product_launch. YouTube video description: source youtube, medium video (or social, pick one and stay consistent), campaign product_launch. QR code on a flyer: source flyer, medium offline (or qr, pick one), campaign spring_sale. Podcast show notes: source podcast_name, medium referral, campaign webinar_may. Influencer link: source influencer_name, medium social, campaign product_launch, with utm_content=influencer_name repeated or the specific post if you want per-creator splits. The pattern to copy: source is always the most specific origin you can name, medium is always one of a short approved list, and campaign is always the promotion name your team already uses everywhere else.

Naming Rules: Lowercase, Underscores, Consistency

Naming rules are where UTM reports are won or lost, because analytics tools treat every variation as a different value. Rule one: always lowercase. Google Analytics treats 'Email', 'email', and 'EMAIL' as three different mediums, and a report split three ways is a report nobody trusts. Rule two: underscores, never spaces or dashes mixed in — 'spring_sale' everywhere, not 'spring sale' in one link and 'spring-sale' in another, because spaces get percent-encoded into unreadable %20 strings and dashes create a second campaign. Rule three: keep a short approved list for medium (organic, cpc, email, social, referral, video, offline) and never invent a new one per link. Rule four: make campaign names match the names your team already uses in ads and email platforms, so the same spring sale lines up across every report. Rule five: version, don't overwrite — 'spring_sale_2026' beats reusing 'spring_sale' for a different year, because reusing a name merges two promotions into one row forever. Write the list down, share it with everyone who creates links, and check new links against it before they go out.

The GA4 Trap: How Source and Medium Map to Channels

The GA4 default-channel trap is the reason clean UTMs still produce confusing reports. Google Analytics 4 sorts sessions into default channel groups using source and medium together, and anything it cannot classify lands in Unassigned, the bucket where insights go to die. The classic failure: medium 'social_media' instead of 'social' — GA4 recognizes 'social' as the Social channel, but 'social_media' matches no rule, so a Facebook campaign tagged medium=social_media lands in Unassigned while the identical campaign tagged medium=social lands in Social. The same trap hits email: medium 'email' maps to Email, but medium 'newsletter' does not, so a newsletter tagged medium=newsletter lands in Unassigned too. Case is a second trap: source 'Facebook' and source 'facebook' are different sources in GA4, and a report that splits Facebook in two understates the channel. The fix is boring and total: use only the approved medium list, keep everything lowercase, and verify each new combination in the GA4 traffic-acquisition report within a day of launch, while the links can still be fixed. When the landing page itself needs checking, our guide to keyword density covers the on-page side of the same campaign.

5 UTM Mistakes That Ruin Your Reports

Five mistakes ruin almost every UTM implementation. First, tagging internal links: UTMs belong on inbound links only, and tagging links inside your own site overwrites the original source, so a Google visitor who clicks a tagged internal banner becomes a campaign visitor and your acquisition report lies. Second, putting personal data in UTMs: never include emails, names, or user IDs in a campaign parameter, because UTM values are stored in analytics and shared with ad platforms, and personal data there is a privacy violation. Third, using spaces, capitals, or mixed separators, which splits one campaign into several rows. Fourth, inventing a new medium per link instead of using the approved list, which fills the Unassigned bucket. Fifth, skipping utm_content and utm_term where they earn their keep: utm_content distinguishes two links in the same email (header versus footer button), and utm_term records the paid keyword for manual CPC links, and both are free precision. The fix for all five is the same habit: lowercase, underscores, approved mediums, inbound links only, and a written naming list. Do that, and your source, medium, and campaign will answer the three questions they exist to answer — where, how, and which promotion — every time.