The five fields and what belongs in each
A tagged link is just your URL with a ? and some key-value pairs stapled on. Nothing about it is clever. The discipline is in agreeing what goes where, and then never deviating.
| Parameter | What it holds | Example |
|---|---|---|
utm_source | The specific property that sent the click. | instagram, whatsapp, google, newsletter |
utm_medium | The channel class. GA4 buckets on this field, so it takes a fixed vocabulary. | cpc, paid_social, organic_social, email, referral |
utm_campaign | The campaign, dated so you can find it later. | diwali-2026-jewellery |
utm_term | The paid keyword. Search campaigns only; usually auto-tagged. | seo-agency-bangalore |
utm_content | Which creative or which link on the page. | carousel-a, footer-cta |
The naming convention is the entire job
This is where UTM tracking actually fails, and it fails silently. Instagram, instagram and IG are three rows in your report. paid-social, paid_social and paidsocial are three channels. Nobody notices for a quarter, and then the quarterly review turns into a data reconciliation exercise.
The fix is boring and it works: one shared sheet, one owner, and four rules everyone follows without thinking.
- Lowercase everything. Values are case-sensitive; field names are not. Assume both are.
- Hyphens between words, never spaces. A space becomes
%20and looks like a different value. - Fix the `utm_medium` vocabulary to a closed list —
cpc,paid_social,organic_social,email,referral,affiliate,qr,messaging— and don't let anyone add to it without asking. - Date the campaign name.
diwali-2026beatsdiwali, because there will be another Diwali. - One person owns the sheet. Everyone else requests a link from it. Free-form link building is how you get eleven spellings of one channel.
Where UTMs break: internal links, WhatsApp and QR codes
Three failure modes account for most broken UTM data, and one of them will already be in your account.
Never tag internal links
Tagging a link from your own homepage to your own pricing page tells GA4 that a new campaign just delivered a visit. It starts a fresh session and overwrites the real source. The person came from Google; your report now says they came from your own banner.
If you want to measure internal link performance, use events, not UTMs.
WhatsApp needs tagging, and inherits it
Untagged WhatsApp traffic usually lands as direct or referral, which in India means a serious chunk of real demand is invisible. Tag every link you send from a broadcast list, a catalogue or a sales rep's chat with utm_source=whatsapp&utm_medium=messaging.
Then remember the second half: a forwarded message carries your UTMs with it. A link that gets forwarded through four groups keeps reporting as your original campaign. That's a feature if you're measuring word of mouth and a distortion if you're measuring one broadcast — so give sales-rep links a distinct utm_content and expect the number to run hot.
Offline QR codes
Bake the UTMs into the URL before you generate the QR, and give every physical placement its own utm_source — packaging-insert, menu-card, event-standee. You only get one shot at this; the code is printed and you can't re-tag it later.
Reading the data in GA4 without misleading yourself
In GA4, tagged traffic appears in the Traffic acquisition report under session source / medium, and in the campaign dimensions. Two things are worth understanding before you present it to anyone.
First, GA4 uses last non-direct attribution for sessions. If someone clicks your tagged email, leaves, and returns by typing your URL, that second session is still credited to the email. That's usually what you want, and it's not what most people assume the number means.
Second, UTMs measure the click, not the cause. A tagged link tells you which touch preceded the visit. It doesn't tell you which touch created the demand. Someone who saw six Instagram posts and then searched your brand name shows up as organic search, and no amount of tagging will fix that. Read the conversion rate alongside the source, keep expectations honest, and see how to read a marketing report for the rest.