The three that matter
utm_source— where the click came from:newsletter,google,partner-name.utm_medium— the kind of channel:email,cpc,social,referral.utm_campaign— which push this is:spring-sale,launch-2026.
Everything else is optional. utm_term carries a paid keyword, utm_content
distinguishes two variants of the same ad, and utm_id ties a click back to a
campaign row in an ad platform.
Consistency is the whole value
UTM tags are only useful if the same thing is always spelled the same way.
email and e-mail, newsletter and news-letter, Spring Sale and
spring-sale each split one campaign into two rows that never get added back
together. Agree a vocabulary — a handful of allowed mediums, one naming pattern
for campaigns — and use presets rather than typing them fresh each time.
Never tag internal links
Tagging a link between two pages of your own site overwrites the original session source in most analytics tools: a visitor who arrived from Google becomes a visitor from your own newsletter the moment they click a tagged internal button. UTM parameters are for traffic arriving from outside.
Tagged URLs and canonicals
A tagged URL is a different URL as far as a crawler is concerned. If those links
get shared publicly or picked up in a feed, add a self-referencing
<link rel="canonical"> to the clean address so ranking signals consolidate.
The Open Graph generator writes the canonical tag
alongside the social meta.
Questions
Why does the tool lowercase everything?+
Because analytics platforms treat parameter values as case-sensitive. Facebook, facebook and FaceBook become three separate sources in the same report, and nobody notices until the numbers are already split across a quarter. Lowercasing at the point the link is made is the only reliable fix; you can turn it off if you have a system that depends on case.
Which parameters are actually required?+
Source, medium and campaign. Term and content are optional and exist for paid search keywords and A/B variants respectively. Sending a link with only utm_source produces a row your reports cannot group with anything else.
Do UTM parameters hurt SEO?+
Only if the tagged URL gets indexed as a separate page. Search engines can treat ?utm_source=x as a distinct URL, splitting signals between it and the clean version. A self-referencing canonical tag on the page solves it, which is why tagged links belong in emails and ads rather than in internal navigation.
Can I tag a link that already has parameters?+
Yes. The builder appends to the existing query string rather than replacing it, preserves the #fragment, and overwrites any utm_ key already present instead of adding a duplicate. A URL with two utm_source values is ambiguous and different platforms resolve it differently.