The short definition
UTM parameters are labels appended to a URL that identify the source of a click.
They look like this:
yoursite.com/services?utm_source=newsletter&utm_medium=email&utm_campaign=summer-check
The page loads normally; analytics reads the labels and records where the visitor came from.
The five parameters
utm_source — where specifically. newsletter, facebook, yelp, van-qr.
utm_medium — the type of channel. email, social, cpc, print.
utm_campaign — which effort. summer-check-2026, freeze-prep.
utm_content — which version, for distinguishing two links in the same message.
utm_term — the keyword, mostly used in paid search and often filled in automatically.
The first three are the ones that matter. The other two are optional.
When to use them
Any link you place somewhere yourself:
- Links in emails and newsletters
- Social posts and profile links
- QR codes on vans, invoices, door hangers or flyers
- Directory listings that permit a link
- Sponsorship and partner pages
When not to
Never on internal links — links between pages of your own site. Tagging those restarts the visitor's session in analytics and makes the original source disappear, corrupting exactly the data you were trying to collect. This is the most common and most damaging UTM mistake.
Not on Google Ads links where auto-tagging is enabled, or the two systems conflict.
Consistency is everything
Facebook, facebook and FB are three separate sources in most analytics tools, which fragments your data quietly.
Agree conventions once — all lowercase, hyphens not spaces, a fixed vocabulary for medium — and write them down somewhere the whole business can see.
The QR code trick worth knowing
QR codes on physical materials can carry UTM parameters, which is one of very few ways to measure whether offline marketing produces anything.
A distinct code on the van, on invoices and on flyers, each with its own tag, turns unmeasurable spend into something you can evaluate.
The one caution
Tagged links are visible in the address bar and can be shared, so avoid putting anything sensitive or personal into them. Campaign names are fine; customer identifiers are not.
Starting
Tag the next email you send and the link in your social profile. That alone recovers traffic currently landing in "direct".
Frequently asked questions
What are the main UTM parameters?
utm_source for where specifically, utm_medium for the channel type, and utm_campaign for which effort. utm_content and utm_term are optional refinements.
Should I use UTMs on internal links?
Never. Tagging links between your own pages restarts the session in analytics and erases the original source, corrupting exactly the data you were collecting.
Why does capitalisation matter?
Because Facebook, facebook and FB are three separate sources in most analytics tools. Agree lowercase conventions once and write them down where everyone can see them.
Can I measure offline marketing with UTMs?
Yes, via QR codes carrying tagged links — a distinct code on the van, on invoices and on flyers. It is one of the few ways to evaluate physical marketing spend.