Google UTM generator: the Campaign URL Builder, the nine parameters, and a naming convention that holds

Google's own UTM generator is the Campaign URL Builder, published at ga-dev-tools.google/campaign-url-builder/. You paste your landing page URL, fill in the campaign fields, and it returns a tagged link you can paste into an email, an ad or a social post. Google Analytics then reports the traffic from that link under the source, medium and campaign you set, in the Traffic acquisition report. Google's help documentation states that for links to websites you should use the Campaign URL Builder, and that for Android app ads you should use the Play Campaign URL Builder instead. Checked 9 October 2026.

The builder is five minutes of work. The part that decides whether your reports are readable in six months is the naming convention behind it, which is most of this page.

The nine parameters, and the three that are not optional

Google's help page "URL builders: Collect campaign data with custom URLs" lists these parameters, checked 9 October 2026:

Parameter	What it records	Google's example
utm_source	The referrer	google, newsletter4, billboard
utm_medium	The marketing medium	cpc, banner, email
utm_campaign	The product, slogan or promo code	spring_sale
utm_id	A campaign ID, matching the IDs used when uploading campaign data
utm_term	The paid keyword
utm_content	Which creative or which link, for telling two versions apart	toplink
utm_source_platform	The platform that directed the traffic, such as a buying platform	Search Ads 360, Display and Video 360
utm_creative_format	The type of creative	display, native, video, search
utm_marketing_tactic	The targeting criteria applied	remarketing, prospecting

Google states directly that when you add parameters to a URL you should always use utm_source, utm_medium and utm_campaign. It also notes that utm_creative_format and utm_marketing_tactic are not currently reported in Google Analytics properties, so adding them is forward planning rather than something you will read this quarter.

A complete, minimal example, following the pattern in Google's documentation:

https://www.example.com/?utm_source=summer-mailer&utm_medium=email&utm_campaign=summer-sale

Case sensitivity, which is where most reports break

Google's UTM best practice guidance is explicit: maintain a strict, case sensitive naming convention for all fields. Keywords with different capitalisation, such as Meta and meta, are treated as different values, and SpringSale and Spring_Sale are considered distinct. That is the single most expensive detail on this page, because it is what splits one campaign into four rows and makes the totals wrong.

The fix is a convention written down once and applied by everyone:

• Everything lowercase, always.
• One separator for spaces, used everywhere. Pick hyphen or underscore and never mix.
• No spaces, no accents, no punctuation beyond your separator.
• One source value per platform, and a distinct value per sub platform. Google's guidance gives fb for Facebook and insta for Instagram as the example.
• One medium per channel, from a closed list. Google's examples include paid_social and organic_search.
• Campaign names that match the exact campaign name in the platform you are buying from, which Google notes prevents one marketing effort splitting into several rows.

A closed list for medium

Source can be long. Medium must not be, because medium is what channel reporting groups on. Agree a list like this and refuse anything outside it:

• email for anything sent from your email platform
• cpc for paid search
• paid_social for paid placements on social platforms
• organic_social for your own unpaid posts
• display for banner and programmatic
• affiliate for partner links
• referral for links from a partner site or a listing
• qr for printed codes, with the print piece in utm_source
• sms and push for messaging
• video for paid video placements

Two rules about what you tag

First, never tag internal links. A UTM on a link between two pages of your own site starts a new session and overwrites the real source, which turns your best acquisition channel into "email" or "newsletter". Tag only links that arrive from somewhere else.

Second, do not tag the links in your Google Ads account if auto tagging is on. Google Ads adds its own click identifier, and layering UTMs on top gives you two systems describing the same click. Pick one, and if you need UTMs for a different tool, use the tracking template so the parameters are applied consistently rather than by hand.

Keep a spreadsheet, not a habit

The builder generates a link; it does not remember what you did. Keep one sheet with a row per tagged link and these columns: date created, owner, destination URL, source, medium, campaign, content, term, the finished URL, and the short link if you use one. Add data validation on the medium column so only your closed list is accepted.

That sheet is what lets a new person tag a campaign correctly in their first week, and it is the record you check when a report shows traffic from a source nobody recognises.

Reading the result in GA4

Tagged traffic appears in the Traffic acquisition report, grouped by session source, session medium and session campaign. Two details save a lot of confusion:

• Google documents that UTM parameters are omitted from the "Landing page and query string" and "Page path and query string" dimensions, and appear instead in the Page location dimension. So do not go looking for your campaign tags in the landing page report.
• Channel groupings are derived from source and medium. A medium outside the expected values lands your traffic in Unassigned, which is almost always a typo rather than a reporting fault.

For the wider picture of how this data fits a measurement plan, see marketing analytics and attribution, and for the reports that matter on the search side, Google Analytics for SEO.

The Google UTM generator questions worth an answer

Which UTM parameters are required?

Google's guidance is to always use utm_source, utm_medium and utm_campaign. Add utm_content when you are testing two versions of the same link, and utm_term for paid keywords.

Are UTM parameters case sensitive?

Yes. Google states that fields are case sensitive and that values differing only in capitalisation are treated as different values. Use lowercase everywhere.

Do UTM tags hurt SEO?

Tagged URLs are for links you place elsewhere, so they are not the URLs you want indexed. Keep a self referencing canonical on the clean URL, which is what tells search engines which version to consolidate on. See canonical tags in SEO.

Can I shorten a tagged link?

Yes. A shortener that issues a redirect passes the parameters through to the destination. Keep the full URL in your spreadsheet so you can rebuild the link if the shortener changes.

What is utm_id for?

It carries a campaign ID that matches the IDs you use when uploading campaign cost data, which is how spend joins up with sessions. Use it when you import cost data, and leave it out otherwise.

Why is my campaign showing as direct or unassigned?

The usual causes are a missing medium, a medium outside the expected values, a tag stripped by a redirect on the way in, or an internal link carrying a UTM and overwriting the original source. Check the finished URL in a browser and confirm the parameters survive every redirect to the landing page.

A source that arrives with no tag

Your naming convention covers every link you control. Buyers who click through from an assistant bring no tag from you, and some bring no referrer either, so they surface as direct.

You can still estimate the effect. Note spikes in direct visits to deep pages with no campaign behind them, then ask an assistant the question those pages answer and see whether it cites you. The UTM cannot be added to an answer, but the answer can be read. AI Knows Us records the sources each assistant cited, which gives the direct bucket a plausible explanation.