- What's a UTM parameter?
- UTM stands for 'Urchin Tracking Module' — a leftover name from Urchin, the analytics company Google acquired in 2005 that became Google Analytics. UTM parameters are five specific URL query parameters (utm_source, utm_medium, utm_campaign, utm_term, utm_content) that GA reads to attribute the click to a campaign. Add them to any link and GA knows exactly where the visit came from instead of guessing from the referrer header.
- Which UTM parameters are required and which are optional?
- Required: utm_source, utm_medium, utm_campaign. Without all three, GA will still record the visit but won't show it as a campaign in the standard reports — the Source/Medium dimension needs both source and medium populated. Optional: utm_term (used historically for paid keywords; less common now) and utm_content (used to A/B test two links pointing to the same URL, like a hero CTA vs a footer CTA in the same email).
- What's the difference between source, medium, and campaign?
- Source = where the click came from (newsletter, facebook, google). Medium = what kind of channel it is (email, social, cpc, organic, referral). Campaign = the marketing initiative (spring_sale_2026, product_launch_v3). One way to remember: source is the brand, medium is the type, campaign is the project. A click from your weekly newsletter promoting a spring sale would be source=newsletter, medium=email, campaign=spring_sale_2026.
- Should UTM values be lowercase?
- Yes — and use underscores instead of spaces. GA treats Facebook, facebook, and FACEBOOK as three different sources, which fragments your reports. Pick a convention (lowercase + underscores is the most common) and stick to it across every link you tag. This tool doesn't force lowercase because some teams have legitimate reasons not to — but it's a strong default.
- Do UTM parameters affect SEO?
- No, with caveats. Search engines treat URLs with different query strings as separate URLs by default, which could in theory fragment ranking signals. In practice, Google canonicalizes them correctly almost all the time, especially for utm_* which it explicitly recognizes. You should still avoid tagging internal links (links from your own site to your own site) — that overwrites the original campaign attribution when a visitor clicks around. Tag only external links: emails, ads, social, partner sites.
- Why are special characters percent-encoded in the output?
- URLs are restricted to a specific set of ASCII characters; anything else has to be percent-encoded (a space becomes %20, an ampersand becomes %26, etc.). This tool runs every UTM value through the URL constructor's searchParams setter, which encodes correctly for every code point — including emoji and non-Latin scripts. If you copy the URL into a browser, it'll decode the values back to what you typed.
- What happens if the URL already has UTM parameters on it?
- The tool strips the existing utm_source, utm_medium, utm_campaign, utm_term, and utm_content before appending the new ones. Pasting an already-tagged URL doesn't produce a URL with duplicate parameters — you get a clean, re-tagged URL. Non-UTM query parameters (like ?ref=… or ?id=…) are preserved.
- Can I use UTM tags with platforms other than Google Analytics?
- Yes. Most analytics platforms — Plausible, Fathom, Matomo, Mixpanel, Adobe Analytics, HubSpot, Marketo — read the same five UTM parameters. The convention is older than Google Analytics itself, and the cross-tool support is the reason UTM has outlived the original Urchin product. Your tagged links work in every modern analytics tool.
- What about GA4's new attribution model — do UTMs still matter?
- More than ever. GA4 uses data-driven attribution by default, which weighs every touchpoint in a conversion path. The utm_source / utm_medium / utm_campaign values are how GA4 identifies each touchpoint — without them, paid clicks, email clicks, and social clicks all collapse into 'Direct' or 'Referral'. If you're running campaigns on more than one channel and not tagging, your acquisition reports are guessing.
- Are these URLs safe to share publicly?
- Yes — UTM parameters carry only the marketing metadata you put in them, not any personally identifying information. Don't put email addresses, names, or IDs in UTM values (that would actually violate GA's terms of service in addition to leaking data through referer headers). Keep values to campaign metadata only.
