Free UTM Link Builder

What UTM tags actually do

A UTM tag is a bit of extra information bolted onto the end of a link. When someone clicks it, that information travels with them and gets picked up by your analytics, so instead of a pile of anonymous visits you can see exactly which post, email or advert sent them.

Without tags, most of that traffic ends up lumped together as direct or referral, which tells you nothing useful. With tags, you can answer the only question that matters: which of the things I am doing is actually working.

The five parameters, in plain English

• utm_source is where the click came from. Facebook, newsletter, google. Think of it as the specific platform.
• utm_medium is the type of channel. Social, email, cpc, offline. This is the one people get wrong most often, and it matters because GA4 uses medium to sort traffic into its default channel groupings.
• utm_campaign is the reason you sent the link. Spring sale, autumn open day, black friday. Keep it consistent so you can compare the same campaign across different channels.
• utm_term is optional and mainly used for paid keywords.
• utm_content is optional and lets you tell two versions apart. Handy for split testing two buttons in the same email.

There is also utm_id, which is only needed if you are importing cost data into GA4.

Three mistakes that quietly ruin your reporting

Capital letters

GA4 is case sensitive. Newsletter and newsletter are two different sources, and your one campaign becomes two half-sized rows in the report. This tool forces lowercase by default for exactly that reason.

Mixing separators

If some campaigns use hyphens and others use underscores, you cannot filter cleanly. Pick one and never deviate.

Tagging Google Ads links

This is the expensive one. Google Ads already passes its own tracking through auto-tagging, which is far richer than anything you can write by hand. Add manual UTMs on top and you override it, losing keyword, device and cost data in GA4. Leave auto-tagging on and leave your Google Ads links alone.

Pick a naming convention and write it down

The tool will format things for you, but it cannot decide your conventions. Agree these before you start and keep them somewhere your whole team can see:

• Use lowercase everywhere.
• Use hyphens between words.
• Keep your list of mediums to a fixed set of about eight and never invent new ones on the fly.
• Include a date or quarter in campaign names if you run similar campaigns repeatedly, so spring-sale-2026 does not blur into last year's numbers.

The value of UTM tagging comes almost entirely from consistency. One person freelancing their own naming style will make a year of data harder to read.

Where to use tagged links

Anywhere you control the link and the destination is your own website. Email campaigns, social posts, paid adverts on platforms without their own tracking, QR codes on print material, podcast show notes, affiliate placements, even your email signature.

Where not to use them: internal links between pages on your own site. Tagging those restarts the session attribution and makes it look like your own website is sending you traffic, which corrupts the very reports you were trying to improve.

Checking your links work

Paste a finished link into a browser, visit the page, then open the realtime report in GA4. Your visit should appear with the source and medium you set. If it lands in Unassigned, your medium is probably one GA4 does not recognise.