What Are UTM Parameters? A Practical Guide With Naming Conventions

The short answer

UTM parameters are tags you append to a link's query string so your analytics tool can tell where a visitor came from. There are five: utm_source, utm_medium, utm_campaign, utm_term and utm_content. A tagged link looks like this:

https://example.com/pricing?utm_source=newsletter&utm_medium=email&utm_campaign=spring-launch

UTM stands for Urchin Tracking Module, after Urchin — the analytics company Google bought in 2005 and turned into Google Analytics. The name survived the product. The parameters are read by the analytics tool on the receiving end; they change nothing about the page itself, and a link works exactly the same with or without them.

The five parameters, and what GA4 does with each

• utm_source (required in practice) — the specific origin: newsletter, google, linkedin. GA4 maps this to Session source.
• utm_medium (required in practice) — the channel type: email, cpc, social, referral. Maps to Session medium, and this is the one GA4 uses to sort traffic into its default channel groups. Get the medium wrong and your campaign lands in "Unassigned".
• utm_campaign — the specific push, so you can group several links together: spring-launch. Maps to Session campaign.
• utm_term — the paid keyword. Largely vestigial now that Google Ads auto-tagging handles this; useful mainly if you run search ads somewhere that doesn't auto-tag.
• utm_content — which link or creative variant was clicked: hero-button versus footer-link. The right place for A/B distinctions.

GA4 also recognises a handful of extras — utm_id, utm_source_platform, utm_creative_format and utm_marketing_tactic — but only utm_id is worth most people's attention, and only if you are stitching cost data from an ad platform onto sessions. Ignore the rest until you have a specific reason.

Two parameters are effectively mandatory: source and medium. GA4 will accept a link with only a campaign name, but with no source or medium it has nothing to file the session under, and the visit ends up credited to direct traffic or an unassigned channel.

A naming convention that survives contact with a team

The single biggest cause of unusable campaign reports is inconsistency, not missing tags. Pick a convention once, write it down, and hold everyone to it.

Where not to use UTMs

Never put UTM parameters on internal links. This is the most damaging UTM mistake, and it is common. When a visitor arrives from Google and then clicks an internally tagged link, GA4 sees new campaign parameters mid-visit and starts a brand new session, re-attributing that visitor away from organic search and onto your internal tag. The original source is destroyed, your session count inflates, and every conversion gets credited to the wrong channel. For measuring internal clicks, use event tracking — that is exactly what it is for.

Two more places to leave them off. Don't tag Google Ads links manually — auto-tagging's gclid parameter carries far richer data, and manual UTMs can override it. And don't put anything private in a UTM: these values sit in the URL, get pasted into chats, appear in referrer headers, and land in shared analytics reports. No names, no email addresses, no customer IDs.

The duplicate-content question

Tagged URLs are technically distinct URLs, so a crawler that finds one treats it as a separate page from the clean version. In practice this is rarely a serious problem — Google is good at consolidating parameter variants, and most tagged links live in email and ads where crawlers never see them. It becomes a real problem when tagged URLs get published somewhere public and start accumulating links of their own.

The protection is a self-referencing canonical tag pointing at the clean URL on every page, which you should have anyway — see the guide to duplicate content for how that works across the rest of a site. Don't block parameters in robots.txt to solve this; that stops the page being crawled without stopping it being indexed, which is worse.

Where the data shows up

In GA4, tagged traffic appears under Reports → Acquisition → Traffic acquisition, where you switch the primary dimension to Session source / medium or Session campaign. Add a secondary dimension of Session manual ad content to see utm_content. Data is not instant — allow up to 24–48 hours before deciding a tag didn't work, and test the link yourself first in the Realtime report, where a tagged visit shows within seconds.

Build your next campaign link

CheckSEO's UTM Link Builder takes each parameter as its own field, handles the encoding, and returns a finished campaign URL you can copy straight into an email or an ad — no manual query strings, and no typo that quietly splits a campaign into two rows.