What Are UTM Parameters?
UTM parameters are query string additions to your URLs that help analytics tools attribute traffic to the correct marketing channel, campaign, and creative.
| Parameter | Purpose | Required? | Example |
|---|---|---|---|
utm_source | Where the traffic comes from | ✅ Yes | google, newsletter, facebook |
utm_medium | The marketing channel type | ✅ Yes | cpc, email, social, banner |
utm_campaign | The campaign name | Recommended | spring-sale-2026 |
utm_term | The paid keyword | Optional | running+shoes |
utm_content | Differentiates ads/links in A/B tests | Optional | hero-cta, sidebar-link |
How UTMs Work in GA4
When a user clicks a UTM-tagged link, GA4 reads the parameters and automatically assigns the session to the correct channel in your reports:
- User clicks
https://example.com?utm_source=google&utm_medium=cpc - GA4 reads
utm_source=googleandutm_medium=cpc - GA4 assigns the session to the Paid Search channel
- The conversion appears under Paid Search in your channel reports
UTM Naming Best Practices
[!IMPORTANT] GA4 is case-sensitive for UTM values.
Recommended Conventions
❌ Bad: utm_source=Google&utm_medium=CPC&utm_campaign=Spring Sale 2026
✅ Good: utm_source=google&utm_medium=cpc&utm_campaign=spring-sale-2026
- Use hyphens not underscores or spaces in campaign names
- Keep values concise — under 100 characters per parameter
- Never UTM internal links — it resets session attribution and inflates traffic data
- Be consistent — create a naming convention doc and share it with your team
Common Source/Medium Combinations
| Traffic Source | utm_source | utm_medium |
|---|---|---|
| Google Ads | google | cpc |
| Facebook/Instagram Ads | facebook | paid_social |
| Email newsletter | newsletter or mailchimp | email |
| LinkedIn organic | linkedin | social |
| Banner ad | ad_network | display |
| Affiliate | partner_name | affiliate |
| QR code | qr_code | offline |