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Channel grouping in GA4 – what are default and custom channel groups?

· Sep 9, 2026· 6 min read

Learn how channel grouping works in GA4 and when it makes sense to create your own traffic classification.

Post title

Analyzing traffic sources correctly helps you understand which marketing activities actually bring users to your website and contribute to your business goals. In Google Analytics 4, channel groups - default, custom, and primary - play an important role in this process. Learn how channel grouping works in GA4 and when it makes sense to create your own traffic classification.

What is channel grouping in Google Analytics 4?

Channel grouping in Google Analytics 4 is a way of organizing traffic sources into broader categories based on specific rules. Instead of analyzing every source and medium combination separately, you can review the performance of broader groups such as organic search, paid campaigns, social media, email, or direct traffic.

Traffic is assigned to a specific channel based on factors such as source and medium values, source platform, and campaign data. However, it is important to remember that channel grouping can apply to different data scopes. In GA4, you will find dimensions related to the user's first channel, session channel, and event attribution:

•First user default channel group - shows the channel through which a user first arrived at your website or app;

•Session default channel group - indicates the channel that initiated a specific session;

•Default channel group - is used to analyze channels in the context of events and attribution.

These dimensions answer different questions and should not be used interchangeably. A user may first arrive at your website through organic search and then return in a later session through an email campaign - both channels can be correctly reflected in GA4, but within different data scopes.

How do default channel groups work in GA4?

Default channel groups in GA4 are created automatically based on rules defined by Google. You cannot edit the definitions of default channels yourself. Google uses a common set of rules that may be updated as the market evolves and new traffic sources emerge.

Organic and direct channels

GA4 default channel groups include categories for organic and direct traffic, as well as traffic from external websites and apps:

•Direct - includes direct traffic, such as visits after entering the website address in a browser or using a saved link. This category may also include traffic for which GA4 has not received enough information to identify another source;

•Organic Search - traffic from organic search results. This group also includes traffic from AI Overviews and AI Mode in Google Search;

•Organic Shopping - traffic from unpaid links on shopping websites and platforms;

•Organic Social - visits from unpaid links published on social media platforms;

•Organic Video - traffic from unpaid links on video platforms such as YouTube, TikTok, or Vimeo;

•Referral - visits from non-advertising links on other websites or apps, such as blogs and news websites;

•AI Assistants - traffic directed to your website from AI assistants such as ChatGPT, Gemini, DeepSeek, Copilot, or Grok. This channel does not include Google AI Overviews or AI Mode - these sources are classified as Organic Search.

Paid channels

Default channel grouping also distinguishes traffic from different types of advertising campaigns. GA4 uses factors such as source and medium and, for integrated advertising platforms, information about the source platform, campaign type, or ad network:

•Paid Search - includes traffic from paid search ads, such as clicks on text ads in Google search results. For manually tagged campaigns, classification is influenced by factors such as the source and a medium indicating paid traffic;

•Paid Shopping - includes traffic from paid product ads on shopping websites and retailer platforms. An example would be a visit to an online store after clicking a product ad;

•Paid Social - traffic generated by paid ads on social media platforms, such as Facebook or Instagram campaigns. GA4 considers the combination of a social source and information indicating that the traffic is paid;

•Paid Video - includes traffic from paid ads displayed on video platforms such as YouTube or TikTok. An example would be a visit to a website after clicking a video ad;

•Display - traffic from display ads, such as banners shown on the Google Display Network. For manually tagged campaigns, medium values such as display, banner, or cpm can result in traffic being assigned to this channel;

•Cross-network - includes campaigns running across multiple advertising networks. In Google Ads, this channel includes campaigns such as Performance Max and Demand Gen;

•Paid Other - includes other paid traffic that does not meet the criteria for more specific channels such as Paid Search, Paid Social, Paid Shopping, or Paid Video;

•Audio - traffic from ads on audio platforms, such as campaigns run on streaming or podcast platforms. When traffic is tagged manually, the audio medium can be used to assign it to this category.

Other channels

GA4 also includes separate groups for several other traffic acquisition methods, so they do not have to be combined with broader categories:

•Email - includes visits from links in email messages, such as newsletters. GA4 can identify this channel when the source or medium indicates email traffic, for example utm_medium=email;

•Affiliates - traffic from affiliate links published by partners, such as websites working with an online store. When traffic is tagged manually, the affiliate medium assigns it to this category;

•SMS - includes visits from links sent in SMS messages, such as promotional campaigns. A source or medium value of sms allows GA4 to classify this traffic into the appropriate channel;

•Mobile Push Notifications - traffic from links in push notifications sent to mobile devices, such as a notification about a promotion in an app. When classifying this traffic, GA4 considers medium values related to push, mobile, or notification.

What determines how traffic is assigned to a channel in GA4?

Google Analytics 4 assigns traffic to channels based on information about where it comes from and the rules defined for individual categories. When grouping traffic, GA4 may take into account:

•source - identifies the specific source of traffic, such as Google, Facebook, or a newsletter;

•medium - describes how the traffic was acquired, such as organic, cpc, email, or affiliate;

•campaign name and ID - help identify traffic associated with specific marketing activities and may be used in its classification;

•source platform - indicates the platform the data comes from, such as Google Ads, Search Ads 360, or Display & Video 360;

•Google Ads auto-tagging - allows information needed to identify and classify traffic from Google Ads campaigns to be passed to GA4;

•campaign type and ad network - for integrated Google systems, GA4 can use this information to distinguish between channels such as Paid Search, Display, or Cross-network;

•rules for manually tagged traffic - when UTM parameters are used, GA4 classifies traffic based on their values and how they match the definitions of individual channels.

Consistent campaign tagging is therefore particularly important. Inconsistent UTM parameter values can cause similar marketing activities to be classified into different channels or prevent traffic from being assigned to the expected category.

What are custom channel groups in GA4?

Custom channel groups in GA4 allow you to create your own traffic categories tailored to how you manage and analyze your marketing activities. Each channel is defined using specific rules, allowing you to classify traffic in greater detail or differently from Google’s default channel grouping.

Creating a custom group does not change the system-defined default channel group or its rules. Instead, it provides an additional way to classify data using criteria such as source, medium, campaign name or ID, source platform, or default channel group.

Google sets limits on the number of custom groups and channels they can contain:

•standard GA4 property - up to 2 custom channel groups;

•Google Analytics 360 - up to 5 custom channel groups;

•number of channels per group - up to 50 in both standard properties and GA360.

Custom channel grouping is particularly useful when Google’s default categories do not fully reflect the structure of your company’s marketing activities or when you need an additional level of detail when analyzing traffic sources. Importantly, custom channel groups can also be applied to historical data, so creating a new group allows you to analyze previously collected traffic according to its rules.

How to create a custom channel group in GA4?

You can create a custom channel group directly in the Google Analytics 4 property settings. Before you start configuring it, determine which traffic sources you want to separate and what rules should be used - this will make it easier to define the conditions for each channel correctly.

To create a custom channel group in GA4:

•go to Admin → Channel groups - this is where you will find the default channel group and any custom groups you have already created;

•create a new channel group - you can start with a copy of the default group or copy one of your existing custom groups;

•give the group a name and, optionally, a description - the name should clearly indicate how or why the traffic is being grouped;

•add or modify channels - you can edit existing categories, remove them, or create your own;

•define the conditions for assigning traffic - rules can use criteria such as source, medium, campaign name and ID, source platform, or default channel group;

•set the channel order - GA4 assigns traffic to the first channel in the list whose conditions are met. If the rules for individual channels overlap, their order directly affects how the data is classified;

•save the group - once you have reviewed the channel definitions and their order, you can complete the configuration and start using the new group in your analysis.

After creating the group, check your reports to make sure traffic is being classified as intended. Pay particular attention to channels with similar or partially overlapping conditions - an incorrect order may cause data to be assigned to a different category than expected.

What mistakes should you avoid when grouping channels?

Simply creating a channel group does not mean that traffic will be classified as intended. Problems can result from both the way campaigns are tagged and the way rules are structured in custom groups. The most common mistakes include:

•inconsistent `utm_medium` values - using different tagging conventions for the same type of traffic can result in it being assigned to different channels;

•overlapping rules - if one traffic source meets the conditions of several channels, the order of the rules may determine where it is assigned;

•incorrect channel order - GA4 assigns traffic to the first channel whose conditions are met, so more specific rules should be ordered appropriately;

•failing to account for new traffic sources - your marketing activities may change over time, so custom rules should be reviewed periodically;

•overly complex grouping - too many conditions can make the classification harder to manage, and Google notes that custom groups containing a large number of fields may negatively affect reports;

•changing definitions without checking how the group is used - editing rules can have different consequences depending on where the group is used. In reports and explorations, new definitions are applied to the underlying data, while changes to audience criteria apply going forward.

The best way to assess whether channel grouping is working correctly is to review actual traffic source data rather than the group configuration alone. In particular, after changing rules or campaign tagging conventions, check whether the data is being assigned to the expected categories.

Channel grouping can also be reviewed as part of a GA4 audit, which may include checking UTM medium values, session sources, custom channel groups, and the quality of traffic acquisition data.

GA4 channel grouping FAQ

Channel grouping in Google Analytics 4 helps organize traffic sources and analyze them using broader categories. Below, we answer the most frequently asked questions about default, custom, and primary channel groups in GA4.

What is a channel group in GA4?

A channel group in GA4 is a set of rule-based traffic source categories. It allows individual sources and medium values to be assigned to broader groups such as Organic Search, Paid Search, Direct, or Email, and their performance to be compared in reports.

What are the default channel groups in GA4?

GA4 uses channels including Direct, Organic Search, Organic Social, Organic Video, Organic Shopping, Referral, AI Assistants, Paid Search, Paid Social, Paid Video, Paid Shopping, Display, Cross-network, Paid Other, Email, Affiliates, Audio, SMS, and Mobile Push Notifications. Traffic is assigned to these channels automatically based on rules defined by Google.

Can you edit the default channel group?

No. You cannot edit the definitions of the system-defined default channel group in GA4. However, you can create your own custom channel groups and set one of them as the primary channel group for the property.

What is the difference between a default and custom channel group?

The default channel group uses rules defined by Google that users cannot modify. A custom channel group allows you to define your own channels and traffic classification conditions, so you can tailor how data is grouped to your company’s needs and reporting structure.

How many custom channel groups can you create in GA4?

You can create up to 2 custom channel groups in a standard GA4 property and up to 5 in Google Analytics 360. Each group can contain up to 50 channels. The system-defined default channel group does not count toward these limits.

Does GA4 automatically recognize traffic from ChatGPT and other AI assistants?

Yes. GA4 has a default AI Assistants channel designed to classify traffic from AI assistants such as ChatGPT, Gemini, DeepSeek, Copilot, and Grok. Traffic from AI Overviews and AI Mode in Google Search is classified as Organic Search instead. If you need a more detailed breakdown of traffic from individual AI assistants, you can use a custom channel group.

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