What are UTM parameters and how to use them correctly

When you send a newsletter or launch a campaign, how does analytics know the visit came from there? From UTM parameters — tags you add to the link. Here's what they mean and how to use them correctly.

What UTM parameters are

UTM parameters are bits of text at the end of a URL (after ?) that describe the visit source. Analytics reads them and attributes the visit to a channel and campaign. Without them the source is often lost — see GA4 (not set) / direct.

The individual parameters

• utm_source — where from (e.g. newsletter, google, facebook).
• utm_medium — channel type (e.g. email, cpc, social).
• utm_campaign — campaign name (e.g. black-friday-2026).
• utm_term — keyword (for paid search).
• utm_content — distinguishes variants (e.g. which button / creative).

How to use them correctly

• Consistently. Keep uniform names (always email, not sometimes e-mail and sometimes Email) — otherwise your channels fragment.
• Lowercase. UTMs are case-sensitive — Facebook and facebook are two different sources.
• Only on external links. Don't tag internal links within the site — it causes false new sessions.
• Watch for redirects that drop UTMs.

Summary

UTM parameters are the basis of source measurement — without them analytics doesn't know where a visit came from. The key is to use them consistently and lowercase. How UTMs connect to conversion measurement is shown in measuring conversions from email.