GA4 channel checker

How GA4 default channel grouping works

Google Analytics 4 uses a set of rules to sort every session into a default channel group. The rules evaluate utm_source, utm_medium, and sometimes utm_campaign to decide whether traffic belongs to Paid Search, Organic Social, Email, Direct, or one of the other default channels. If a session does not match any rule, it falls into "Unassigned" — the analytics equivalent of a lost-and-found box.

The default channels

GA4 defines the following default channel groups, evaluated in priority order:

Why your UTM medium matters most

The single most important value for channel classification is utm_medium. If you tag a Google Ads campaign with medium=cpc, it lands in Paid Search. Use medium=paid and it still works. But tag it as medium=google-ads and GA4 has no matching rule — your paid traffic silently lands in Unassigned, invisible in channel reports.

Common mistakes that cause Unassigned traffic

The most frequent cause of Unassigned traffic is using a utm_medium value that GA4 does not recognize. Medium values like "social," "ad," "banner-ad," or "paid-search" do not map to any default channel rule. Stick to the standard values: cpc for paid search, paid-social for paid social, email for email, and referral for referral traffic. Case matters too — "CPC" is not the same as "cpc" in GA4.

How this checker works

Paste any URL and the tool extracts the UTM parameters, then evaluates them against the same rules GA4 uses for default channel grouping. The result shows which channel your traffic will land in, along with an explanation of which rule matched. Everything runs in your browser — no data is sent anywhere.