Why Pinterest Ads Need UTM Parameters (epik Isn't Enough)

Your Pinterest Ads are showing up as "referral" traffic in GA4 instead of "Paid Social." You're spending money on ads, but GA4 can't tell the difference between paid clicks and organic pins.

The issue? Pinterest's epik parameter tracks conversions for Pinterest, but GA4 doesn't recognize it for channel classification. Without UTM parameters, all Pinterest traffic looks like referral traffic.

Why this happens

Pinterest automatically appends its epik parameter to track ad clicks, conversions, and attribution back to specific Pins and audiences. This works great for Pinterest's internal reporting.

However, GA4 doesn't recognize the epik parameter for traffic classification. Without UTM parameters, GA4 sees:

• Referrer: pinterest.com
• No UTM parameters present
• Classification: Referral traffic (not Paid Social)

Unlike Google's click IDs (gclid, gbraid, wbraid) which GA4 recognizes and classifies as paid traffic, non-Google platform parameters like epik require manual UTMs to properly identify traffic as paid.

The fix

Add UTM parameters to your Pinterest Ads URLs. Both epik and UTMs work together without conflict.

Steps:

1. Open Pinterest Ads Manager
2. Edit your ad campaigns
3. Add UTM parameters to destination URLs:
   • utm_source=pinterest
   • utm_medium=paid-social (or cpc or paidsocial)
   • utm_campaign={your-campaign-name}
4. Save changes

Pinterest will continue auto-appending epik for its own tracking, while UTMs ensure GA4 properly classifies traffic as Paid Social. GA4 does NOT create duplicate sessions—both parameters coexist without issues.

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Related: Platform Click ID Conflicts Documentation