Dimensions and Metrics Used in GA4

This page is for Google Analytics 4 (GA4). Find a page like this for Universal Analytics (UA)

EPA content related to Google Analytics is changing.

Google's legacy platform, Universal Analytics (UA), will reach end of life in mid-2023 with a one-time extension for contracting clients such as EPA until July 1, 2024. See KB article.

In these Web Analytics pages, content for Universal Analytics is marked "Google Universal Analytics (legacy)."

Content for the new platform, Google Analytics 4, is marked "Google Analytics 4 (GA4)."

On this page:

Dimensions and Metrics
Commonly Used Dimensions
Commonly Used Metrics

Dimension and Metrics

Every report in Google Analytics is made up of dimensions and metrics.

A dimension is an attribute of website data or Google's data model. It describes the pages, content, visitors to your web pages, or the data captured in Google Analytics. It's usually text as opposed to numbers. An example of a dimension is Event name, which shows the name of an event that a visitor triggers on the website (such as "click" or "page_view").
A metric is a quantitative measurement, such as a count, average, ratio, percentage, and so on. It's always a number as opposed to text. An example of a metric is Event count, which shows the total number of times an event is triggered.

For instance, a commonly used report in Google Analytics 4 would include the Dimensions Page path + query string (page URLs) and Event name (filtered to page_view), with the Metric Event count, to display the number of times specific pages were viewed in the time period of the report. The image below shows such a report for page path beginning with "/radon" and event name "page_view":

Image shows sample report with dimension 'page path + query string' and metric 'event count' in Google Analytics 4.

Full List of dimensions and metrics used in EPA's Google Analytics 4 property

Google Analytics has a very long list of Dimensions and Metrics, some of which are only useful for commercial sites. These dimensions and metrics are either predefined by Google or customized for a property such as EPA's website. The tables below offer descriptions of dimensions and metrics commonly found in GA reports. You can view Google's predefined dimensions and metrics in this Analytics Help article.

Common Google Analytics Dimensions

Every piece of data in GA4 is either an aspect of site Events (event parameters), Sessions (session properties), or Users (user properties). Dimensions below are grouped below by Event, Session, and User.

Common Google Analytics Dimensions
Event based dimensions
Dimension	Description	Application
Event name	The name of an event. For example, if a user views a web page, the text 'page_view' populates the dimension.	To see reports for a variety of activities on your pages, filter this dimension on specific values. For example: page_view view_search_results downloads external_link scroll
Landing page	The page path and query string associated with the first pageview in a session.	Filter on this dimension to see search terms that lead users to your page(s). See Search Terms: incoming
Link URL	The full URL for an outbound link or file download.	Use this dimension as a row to view file path for PDF files or URLs of external links. See PDF Link Analysis See Page Traffic: external links
Page path + query string	The page path and query strings in a URL.	Use this dimension as a row and filter to limit a report to include or exclude a particular page or set of pages. See Page Traffic
Page referrer	The referring URL, which is the user's previous URL and can be your website's domain or other domains.	Filter on this dimension to see page traffic or search terms that lead users away from your page(s). See Page Traffic: outgoing See Search Terms: outgoing
Page title	The title of the page in WebCMS.	Filter on this dimension as an alternative to Page path + query string.
Search Terms	Terms used to search your website (site search) or to find your website (e.g., from Bing or Google).	Use this dimension as a row and filter on Session Default Channel Group in order to report Terms used for site search or organic search in relation to you pages or web area. See Search Terms Analysis
Web area	A custom dimension that contains the text of the web area name as it appears in WebCMS page metadata.	Filter on this dimension as an alternative to Page path + query string, to limit a report to a web area.

Session based dimensions
Dimension	Description	Application
Session Default Channel Group	The default channel group by which the user was first acquired. Default channel groups include 'Direct', 'Organic Search', 'Paid Social', 'Organic Social', 'Email', 'Affiliates', 'Referral', 'Paid Search', 'Video', and 'Display'.	For reports that look at search terms, use a filter on Session Default Channel Group exactly matches “Organic Search” to see search terms used in organic search, or does not exactly match “Organic Search” to see search terms used in internal site search.
Session Source / Medium	The source and medium that was associated with the start of a session. Source: Users who return to your website from Google Search show as "google" in the Session source dimension. Examples include “google”, “youtube”, and “gmail”. Medium: The method for acquiring users to your website or application. Examples include: 'email': users who click a link in an email marketing campaign 'organic': users who click a link from a search engine 'referral': users who click a link on a website (e.g., a link in a video description) '(none)': direct traffic	Session based segments can be created using session properties, allowing you to focus on a subset of all sessions or to compare multiple segments. For example, you could create a segment comparison to highlight differences and similarities between session medium "organic" vs. "referral."

User based dimensions
Dimension	Description	Application
Browser	The browser from which user activity originated. Typical browsers include 'Chrome', 'Edge', 'Firefox', 'Internet Explorer', 'Opera', and 'Safari'.	It can be a good idea to monitor the trends associated with User technology, including Browser, Operating System, Device Category, Platform, and Screen Resolution.
City	The city from which user activity originates.	Examine user activity on your pages by city.
Country	The country from which user activity originated.	Examine user activity on your pages by country.
Device Category	The type of device from which user activity originated. Device categories include 'desktop', 'mobile', and 'tablet'.	Track a metric like User Engagement (see metrics below) by Device Category to more deeply understand user activity on your pages.
New / established	New and established users who first opened your app or visited your website within the last 7 days.	User based segments can be created using user properties, allowing you to focus on a subset of all users or to compare multiple segments.
Operating System	The operating system used by visitors on your website or application. Typical operating systems include 'Android', 'Chrome OS', 'Macintosh', and 'Windows'.
Platform	The method by which users accessed your website or application. Platforms include 'Android', 'iOS', and 'Web'.
Region	The geographic region from which user activity originated.	Examine user activity on your pages by region.
Screen Resolution	The width and height (in pixels) of the screen from which user activity originates. Examples include '1920x1080', '1440x900', and '1366x768'.

Commonly Used Metrics

Every piece of data in GA4 is either an aspect of site Events (event parameters), Sessions (session properties), or Users (user properties). Metrics below are grouped below by Event, Session, and User.

Common Google Analytics Metrics
Event based metrics
Metric	Definition	Application
Entrances	The number of times that the first event recorded for a session occurred on a page or screen.
Event count	The number of times users triggered an event.
Event count per user	The average number of events triggered per user.
Events per session	The average number of events per session.
Exits	The number of times that the last event recorded for a session occurred on a page or screen.
Views	The number of web pages your users saw. Repeated views of a single page are counted.
Views per user	The average number of web pages viewed per user.
Session based metrics
Metric	Definition	Application
Bounce rate	The percentage of sessions that were not engaged sessions.
Engaged sessions	The number of sessions that lasted 10 seconds or longer, or had 2 or more page views.
Engagement rate	The percentage of sessions that were engaged sessions.
Sessions	The number of sessions that began on your website.
User based metrics
Metric	Definition	Application
Active users	The number of distinct users who visited your website or application. An active user is any user who has an engaged session or when Analytics collects: the first_visit event or engagement_time_msec parameter from a website the first_open event or engagement_time_msec parameter from an Android app the first_open or user_engagement event from an iOS app Note: The Active users metric appears as "Users" in Reports.
Average engagement time	The average time that your website was in focus in a user's browser or an app was in the foreground of a user's device. Average engagement time = Total user engagement durations / Number of active users.
Average engagement time per session	The average engagement time per session.
New users	The number of new unique user IDs that logged the first_open or first_visit event. The metric allows you to measure the number of users who interacted with your site or launched your app for the first time.
Returning users	The number of users who have initiated at least one previous session, regardless of whether or not the previous sessions were engaged sessions.
User engagement	The length of time that your app screen was in the foreground or your web page was in focus.