UTM parameters are tags added to a link so analytics can tell where a visitor came from. Use lowercase, use hyphens, decide your source and medium values in advance, and never tag internal links on your own site.
Those four rules prevent almost every UTM problem that reaches an analytics report.
What each parameter is for
There are five and only three are usually necessary.
- utm_source: where it came from. The specific platform: newsletter, linkedin, partner-name
- utm_medium: the type of channel: email, social, cpc, referral. This is the one people misuse most
- utm_campaign: which effort it belongs to: spring-launch, black-friday
- utm_content: which version of the link, for A/B tests or two links in one email
- utm_term: paid keyword, largely legacy outside search ads
The convention that survives a team
Almost every broken UTM report traces back to inconsistency rather than to a wrong idea.
Analytics treats Email, email and EMAIL as three different mediums, so your one channel appears as three rows and every total is wrong. Lowercase everything, always.
Use hyphens rather than spaces or underscores, since spaces become encoded characters that make reports unreadable. And keep a single list of permitted source and medium values somewhere the whole team can see, because the value of a convention is entirely in it being shared.
The mistake that erases your data
Never put UTM parameters on links between pages of your own site.
Doing so starts a new session and overwrites the original source, so a visitor who arrived from a search and then clicked an internally tagged link is recorded as coming from wherever that internal tag said. You have not measured the journey, you have destroyed the record of it.
If you need to know which internal button was clicked, use event tracking. UTMs are for traffic arriving from outside.
What not to tag
Tagging everything is as unhelpful as tagging nothing.
Do not tag paid search links if your ad platform is already connected to analytics, since the automatic tagging is better and the two can conflict. Do not tag links you paste into a public page, because anyone who copies that link spreads your campaign tag across the internet. Do not tag your own homepage in your email signature and then wonder why direct traffic collapsed.
A starter convention
If you need something to adopt today, this works and is easy to remember.
Source is the specific place, always lowercase: newsletter, linkedin, instagram, partner-acme. Medium is one of a fixed short list: email, social, cpc, referral, affiliate. Campaign is the thing you would name it in conversation, hyphenated. Content only when you genuinely have two versions to compare.
Write those rules in one document, put the link to it wherever people build links, and review the channel report once a month for values that do not match. Fixing the drift early is a five minute job; fixing a year of it is not possible.
Common questions
- Should I put UTM parameters on internal links?
- Never. It starts a new session and overwrites the original source, so a visitor who arrived from search is recorded as coming from your internal tag. Use event tracking for internal clicks.
- Why is my UTM data split across multiple rows?
- Almost always capitalisation. Analytics treats Email, email and EMAIL as three different mediums, so one channel appears as three rows and every total is wrong. Lowercase everything and use hyphens rather than spaces.
- Which UTM parameters are actually required?
- Source, medium and campaign. Content only when you genuinely have two versions to compare, and term is largely legacy outside paid search.
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