- GA4 counts users across both your website and app (if you have one) but UA only counts website users.
- ‘Users’ in GA4 reports means Active Users. ‘Users’ in UA reports means Total Users.
- Both GA4 & UA count Total Users and New/Returning Users, but they're defined differently in each platform.
- GA4 has Active Users as a metric but UA doesn't.
- You won’t see ‘Active Users’ as the metric name in standard GA4 reports, but you will see the Active Users metric in Explorations.
- GA4 Total Users vs Active Users aren't hugely different - the main difference is that Active Users definitely had an engaged session.
- Comparing GA4 users to UA users will never be apples to apples because of differences in how each platform measures the data. But there are approximations you can use if you're desperate for YOY user comparisons.
- User ID setup in UA vs GA4 and potential data filters in UA can both cause user metrics to be off if comparing data from the two platforms.
Because of these differences, if you were to compare User count in UA vs GA4 for the same time period you’d see different numbers.
Keep reading for more insight on each of these points.
GA4 Has More User Metrics than Universal Analytics
UA had 2 user metrics:
- Total Users
- New Users
GA4 has 3 user metrics:
- Total Users
- New Users
- Active Users
Both UA and GA4 also offer Returning Users as a metric (it’s the inverse of New Users).
GA4 & UA Define User Metrics Differently
Here’s what user metrics mean in each platform, and how they’re measured.
Total Users in UA
In UA, Total Users is defined as “Total number of users”
This was measured by counting the number of users who had at least one session within the defined date range. Total Users is the primary user metric in UA, so when you look at reports and just see “Users”, this is where the data is coming from.
Total Users in GA4
In GA4, Total Users is defined as “Total number of unique users who logged an event”
This is measured by counting the number of unique users with at least one session, who also had at least one event.
The easiest event a user can trigger is staying on the page for a minimum of 10 seconds, which counts as an ‘engaged session’ event (unless you changed the engaged session calculation). But any other event (such as scrolling down the current page, viewing another web page or any number of things) also counts.
Total Users Takeaway:
- Total Users is the primary user metric in UA, but not in GA4.
- In UA, if a user landed on a web page, glanced around but didn’t scroll or click on anything, and left within 10 seconds, one session and one user count would be logged.
- In GA4, if a user lands on a web page, glances around but doesn’t scroll or click on anything, and leaves within 10 seconds, it will not count as a session and no user count will be logged.
New Users in UA
In UA, New Users is defined as “Number of users who interacted with your site for the first time”
This was measured with the User ID feature if you set it up. If not, New Users was measured by counting users who did not have a GA cookie in their browser from a previous site visit.
New Users in GA4
In GA4, New Users is defined as “Number of users who interacted with your site or launched your app for the first time”
This is measured by counting new unique User IDs that trigger a <code>first_visit</code> (site) or <code>first_open</code> (app) event. Like UA, GA4 does not automatically create and track User IDs - you have to set it up. User IDs can only be assigned to users who sign up for something or log in to your website. Because it’s tied to your website’s database, User ID is a more accurate identifier of new users.
For users who visit your website and don’t sign up or log in to anything, GA4 assigns a unique Client ID which is stored as a first-party browser cookie. This is used in place of a unique User ID to count new users (it shows up as “Effective user ID” in User Explorer), but it’s not as accurate.
Client ID is tied to a specific device and browser, so a user who visits your site from their smartphone in the morning and from their laptop in the afternoon would count as two users. Users can also block or remove browser cookies, which erases the stored Client ID and skews new/returning user counts.
<div class="post-note">GA4 also provides New/Established as a user dimension (only applies to apps) where a user is considered ‘established’ if they first opened your app more than 7 days ago, and ‘new’ if they first opened your app within the past 7 days.</div>
New Users Takeaway:
- UA & GA4 both rely on User ID to track new and returning users, and default to using Analytics cookies if you don’t set up User ID.
- GA4 counts New Users across your website and app, but UA only tracked New Users on your website.
Active Users in GA4
Active Users as a metric is exclusive to GA4 and never existed in UA.
<div class="post-alert">Universal Analytics did have an Active Users report which used the term 'Active Users', but it had nothing to do with engagement. The UA Active Users report (found under Audience) showed the number of total users who visited your website at least once within a set of defined date ranges.</div>
Active Users in GA4 is defined as the count of unique users who:
- Visit your website or app and have an engaged session OR
- Trigger a <code>first_visit</code> / <code>first_open</code> event OR
- Trigger an <code>engagement_time_msec</code> event parameter on your website or Android app (equivalent to <code>user_engagement</code> events in iOS apps)
In other words, to be counted as an Active User the site visitor must have an engaged session, be a new user, or spend time on your website or app.
Which means to be excluded from Active Users, a site visitor must:
- Be a returning user
- Spend less than 10 seconds on the site or app
- Not take any actions that trigger the <code>engagement_time_msec</code> event parameter
My theory: it seems like the point of creating Active Users is to filter out users who have your website open in a tab (or your app open but backgrounded) who may open up that tab or app briefly before closing or navigating away again. If this (or a different theory) is ever confirmed I'll update this article!
Brief Digression: How Does User Engagement Time Work?
<code>engagement_time_msec</code> is an automatically collected event parameter that measures user engagement. It records time in milliseconds and sends "time measurement packets" to Analytics whenever:
- A new event is triggered
- A user moves moves away from your site's browser tab
- A user backgrounds an app screen
- A user closes the browser tab/window or app
- A user navigates to a new web page or app screen
- Your website or app crashes
When one of the above happens, GA4 takes the current packet of accrued user engagement time and attaches it to the subsequent triggering event. The data is used to populate metrics including 'User engagement' and 'Average engagement time' in GA4 reports.
But it doesn’t add user engagement time to <code>first_visit</code>, <code>session_start</code> or <code>page_view</code> events because there was no prior engagement to measure.
GA4 Total Users vs GA4 Active Users
Total Users and Active Users are pretty similar metrics in GA4, and the count is often not very far off. Active Users is usually slightly lower than Total Users because the requirements to be counted as an “Active User” are a little more specific.
For example, a user who triggers a <code>first_visit</code> event but leaves within 10 seconds would be counted under New Users and Total Users, but not Active Users (because they didn’t have an engaged session).
Active Users Takeaway:
Active Users is the primary user metric in GA4. When you look at a standard report and see “Users”, they’re talking about Active Users. But if you’re looking at an Exploration report you’ll see a metric called Active Users.
GA4 & UA Have Different Primary User Metrics
UA had Total Users as the primary user metric, and GA4 has Active Users as the primary user metric. “Users” is displayed in both UA and GA4 standard reports, so it looks like the same thing but it’s not.
Can You Compare Users in GA4 to Users in UA?
If you didn’t set up GA4 early enough to have year-over-year data by now, then you might want to compare your GA4 users to UA users to see if you’ve grown your audience.
Google has a couple suggestions for how to do an approximate comparison:
<blockquote class="quote">“Depending on how frequently your users return to your website, the Total Users metric in UA and the Active Users metric in GA4 may be more or less similar.”</blockquote>
<blockquote class="quote">“You can compare Total Users from UA to Total Users in GA4 by using Explorations in GA4 to find your total users number. These numbers may be more comparable than the Users metrics in the GA4 reports due to the differences in definitions.”</blockquote>
Both of these insights come from this Google documentation page.
Settings for User Identity Might Be Different in UA vs GA4
As touched on earlier, GA4 and UA both offer the User ID feature if you set it up (and default to using browser cookies if you don’t). If you set up User ID differently in each platform, that would change how user metric data is collected.
User Data in UA Reports Might Be Filtered (But Not in GA4)
In Universal Analytics if you went to Admin > View > Filters you could add a filter to exclude or include specific types of data. An example of a common use for this was creating a filter to only look at data from a specific subfolder/directory or subdomain (or to look at data from everywhere except a specific subfolder or subdomain).
GA4 doesn’t support these types of data filters. There are only two types of data filters for GA4 right now:
- Filter out internal traffic (by IP address)
- Filter out developer traffic from debug mode
So if your UA data was filtered in ways your GA4 data isn't, that’s another reason user metrics in UA vs GA4 wouldn’t match up.
<div class="post-note-cute">This article came about because we noticed that our page about GA4 sessions vs UA sessions was getting clicks from organic search for queries about users, even though a user metric comparison isn’t covered on that page. If you’d like to learn more about using Search Console data to discover new content opportunities, or if you have questions about anything analytics related, don't hesitate to reach out: firstname.lastname@example.org</div>
Resources used to create this article
- [GA4] Understand user metrics (Google documentation)
- [GA4] User engagement (Google documentation)
- [GA4] Predefined user dimensions (Google documentation)
- [GA4] Analytics dimensions and metrics (Google documentation)
- [UA → GA4] Comparing metrics: Google Analytics 4 vs. Universal Analytics (Google documentation)
- [UA] How users are identified for user metrics (Google documentation)
- [UA] About the User-ID feature (Google documentation)
- [UA] Active Users
- How to configure User ID in Google Analytics 4 (Analytics Mania)
- Complete guide to User Engagement in Google Analytics 4 (VakulskiGroup)
- User ID in Google Analytics Explained with Examples (OptimizeSmart)