GA4 Channel Grouping Simulator

GA4 channel grouping is a rule-based system that automatically classifies your website traffic into channels like Paid Search, Organic Social, Email, Display, etc. GA4 uses the utm_source and utm_medium parameters (along with referrer information) to determine which channel each session belongs to. This classification helps you understand which marketing channels are driving traffic and conversions.

GA4 runs your traffic through a hierarchical set of rules in a specific order: Paid Shopping → Paid Search → Paid Social → Paid Video → Display → Paid Other → Organic Shopping → Organic Social → Organic Video → Organic Search → Email → Affiliates → Referral → Direct. The first matching rule wins.

For example, if your utm_medium contains 'cpc' and utm_source is 'google', GA4 assigns it to Paid Search. If your utm_medium is 'email', it goes to the Email channel. The exact combination of source and medium determines the final channel.

Traffic appears in the "Unassigned" channel when your utm_medium value doesn't match any of GA4's recognized patterns. Common causes include: using custom medium values like "newsletter" instead of "email", typos in utm_medium, uppercase letters (GA4 is case-sensitive), or conflicting source-medium combinations like "google" + "social".

For example, utm_medium=newsletter creates Unassigned traffic because GA4 only recognizes utm_medium=email for email campaigns. This breaks your channel attribution and makes it impossible to measure campaign performance accurately.

GA4 recognizes specific utm_medium patterns for each channel:

• Paid campaigns: cpc, ppc, paidsearch, paid (or any medium containing "cp") • Email: email (exact match required) • Social: social, social-network, social-media, sm, paidsocial • Display: display, banner, cpm, expandable, interstitial • Referral: referral, app, link • Affiliate: affiliate, affiliates • Video: video • Organic: organic (typically auto-assigned by GA4)

Using non-standard values like "newsletter", "promoted", or "paid-social" will result in Unassigned traffic.

You cannot modify GA4's Default Channel Grouping rules, but you can create custom channel groupings with your own rules. To do this, go to GA4 → Admin → Data Display → Channel Groups → Create new channel grouping.

However, it's usually better to use GA4-recognized utm_medium values so the Default Channel Grouping works automatically across all reports. Custom channel groups require ongoing maintenance and don't apply retroactively to historical data.

Use this GA4 Channel Grouping Simulator to instantly see which channel GA4 will assign your URLs to before you launch campaigns. Simply paste your URL with UTM parameters and the simulator will show you the exact channel classification.

Alternatively, you can test live by: (1) Creating a link with your UTMs, (2) Clicking it yourself, (3) Checking GA4 → Realtime → Traffic sources within a few minutes to verify the channel assignment. If it shows 'Unassigned', you need to fix your utm_medium parameter.

Correct channel grouping is critical for accurate marketing attribution and ROI measurement. If 20% of your traffic ends up in 'Unassigned', you can't determine which campaigns drove those conversions, leading to poor budget allocation decisions.

For example, if your email campaigns use utm_medium=newsletter (not recognized by GA4), all that traffic becomes Unassigned. You might think email underperforms when it's actually your best channel. This can lead to cutting budgets from high-performing channels and investing in underperforming ones.