UTM parameters: what they mean, how to name them and how to keep GA4 reports intact

What UTM parameters are and what they do

UTM parameters are fragments added to the end of a URL that pass information about the campaign a visitor came from to Google Analytics. According to Google Analytics help on URL builders, the parameter values are sent to Analytics when a user clicks the link and show up in the Traffic acquisition report.

The tags tell GA4 which campaign a visit came from, so you can compare a newsletter, ads and posts in one report. Without them you cannot build that comparison in one report.

A tagged address looks like this: https://www.example.com/?utm_source=summer-mailer&utm_medium=email&utm_campaign=summer-sale. The part after the question mark holds the parameters, joined with &.

Which UTM parameters belong in every address and which are optional

Every address with UTMs should carry three parameters: utm_source, utm_medium and utm_campaign. That is what Google Analytics help says, and each one is shown below with an example:

• utm_source: where the traffic came from, for example google, a newsletter or a platform name.
• utm_medium: through which channel, for example cpc, email or banner.
• utm_campaign: as part of which campaign, for example a product, a slogan or a promo code.

The remaining parameters organise reports in more detail and are optional. The table below collects them from Google Analytics help.

The last two parameters in the table, utm_creative_format and utm_marketing_tactic, are not currently reported in Google Analytics properties according to Google's help, so the others are enough for day-to-day work.

How utm_medium decides the traffic channel in GA4

The default channel group in GA4 assigns manually tagged traffic to a channel mainly from source and medium, so a wrong utm_medium puts the visit in the wrong channel. The rules are described in Google's help on the default channel group, and Google notes that the group cannot be edited.

For the Paid Search, Paid Social and Paid Video channels the condition is shared: the medium must match the pattern ^(.*cp.*|ppc|retargeting|paid.*)$. The source name alone is not enough. The table below shows where a few typical tags end up in the report.

UTM or auto-tagging in Google Ads: which one takes priority

In Google Ads campaigns, auto-tagging takes priority in GA4 over manual UTM tags. Google Ads help on auto-tagging states that in GA4 auto-tagging is prioritised because there is no option to override it.

Auto-tagging appends a GCLID parameter, the Google Click Identifier, to the address. According to the same page it is needed to track conversions in all browsers, to import key events from Google Analytics and other sources, and to bring campaign cost data into GA4 reports. It is on by default for new accounts.

Google also appends gad_* parameters, such as gad_source and gad_campaignid. According to the help page on gad_* parameters, your redirects must keep them as top-level parameters, and a small share of sites reject unknown parameters and return an error. If you close sales offline, auto-tagging is also a condition for importing offline conversions, which we describe in Offline conversions in Google Ads.

In practice the split is simple. In Google Ads you turn auto-tagging on and do not treat UTMs as the source of truth for those campaigns. You add UTMs everywhere else: newsletters, Meta Ads, LinkedIn Ads and TikTok Ads, partner links and posts.

How to name sources, media and campaigns so reports do not fall apart

A naming convention is a written list of values for source, medium and campaign that everyone on the team uses. Google Analytics help recommends a strict convention: one unique utm_source per platform, one utm_medium per channel and one utm_campaign name that matches the campaign name in the platform, with every field in lowercase.

Case matters. According to Google Analytics help, “Meta” and “meta” are treated as different values, and so are “SpringSale” and “Spring_Sale”. The table below shows the convention we suggest as a starting point.

Where you can, use the platform's dynamic parameters. Google gives {{campaign.name}} for the campaign name and {{site_source_name}} for the source as examples, because the platform fills in the value for you and there are no typos. When a marketing agency runs your ad accounts, agree the convention before the first campaign, while no report exists yet.

Which tagging mistakes most often break the data

The most common UTM mistakes are inconsistent names, a wrong medium and parameters that disappear along the way. In our audits, attribution problems most often come from one of the causes below:

• Capital letters and name variants: “Newsletter”, “newsletter” and “news_letter” create three rows where there should be one.
• A medium outside the GA4 rules: a value such as “social” on a paid ad moves traffic to an organic channel, as in the Facebook ad example.
• Parameters lost on redirects: short links and cross-domain redirects can trim the address down to the bare path, so test the full route from click to landing page.
• A site that rejects unknown parameters: some servers return an error for an address with parameters, which Google Ads help confirms for gad_* parameters.
• No single owner of the naming table: everyone invents their own values and after half a year the report is useless for comparisons.

We advise against UTMs on a site's internal links, for example on banners on the home page. Such tags describe a visit from outside and do not fit clicks inside the site, so events are a better way to measure banners.

How to check that UTMs work

Checking UTMs takes a few minutes and has three steps:

• Open the tagged address in an incognito window and confirm that the parameters stay in the address bar after the page loads.
• In GA4 open the realtime report and check that source and medium show up as you entered them.
• After a few days open the Traffic acquisition report and check that the campaign has one row and the traffic landed in the right channel.

Two technical notes. Google's help says UTM information is not captured in the “Landing page + query string” and “Page path + query string” dimensions, but in the Page location dimension. If the GA4 tag itself is not working, no UTM will help, so start with the GA4 Audit, which scans your deployed measurement, and find the full checklist in GA4 audit: a checklist. We describe measurement setup and cleanup on the GA4 service page.