How to use Segment Overlap in Google Analytics 4

Segment Overlap is a new report available in Google Analytics 4 for free. It allows us to compare up to 3 segments between themselves and see if they overlap. As a result, you can gather new insights about users and build new GA4 audiences for remarking purposes.  

This article is an episode of the series of articles about Google Analytics 4 Explore. The place where you can build reports by drag&drop interface. If you want to improve your knowledge of the rest reports available in GA4 Explore, don’t hesitate to read the articles below:

  1. Free form Exploration
  2. Funnel Exploration
  3. Path Exploration
  4. Cohort Exploration
  5. User Explorer
  6. User Lifetime 

So, let’s get started with Segment Overlap. 

What is Segment Overlap, and when should you use it?

As mentioned above, segment overlap in Google Analytics 4 is a new report unavailable in Universal Analytics. You can use it to compare up to three segments of our users and see if they overlap. You can then create new segments based on your findings, which you can apply to other Explorations techniques and Google Analytics 4 reports.

Segment Overlap Screenshot
GA4 Segment Overlap

For instance, we used this report for one of my clients to understand which devices different demographic groups use on the website. Therefore, we used the following segments:

  1. Desktop Traffic
  2. Age 18-25, 25-34
  3. Age 45-65+

We found that in 90% of cases older generation was eager to use the desktop as their primary device, while for the younger generation (18-34), it was the opposite; they preferred to use non-desktop (mobile) devices to enter the website and make a purchase. 

As a result, it induces us to look at the website from different lenses and optimise the flow differently. After additionally watching session recordings, we could increase the conversion rate to 243%. 

You can do a similar analysis and catch some insights to redesign your website to improve the business bottom line. Still, before doing that, you should know how to use the Segment Overlap report interface. Therefore, let me explain it in detail to you.

GA4 Segment Overlap Report Interface

First, in order to create a segment overlap report in Google Analytics 4, you should take a few actions:

  1. Open GA4 and go to Explore tab

    Step 1 Open GA4 Explore

  2. Click on Template Gallery and Select “Segment Overlap”

    Step 2 Select Template Segment Overlap

After these steps, you should modify the settings to see what you need. For this article, I will use the publicly available GA4 property that stores data about ecommerce.  If you are not an Ecommerce business, you can change the events you use. All instructions below will apply to any company.

For our case, I will check how many active users accessed the Merchandise store using desktop and mobile devices. 

GA4 Segment Overlap Parts

So, as you can see in the screenshot above, the report consists of three parts. The first part is called “Variables”, the second “Tab Settings”, and the last one “Report View”.

Report part #1 – Variables

Let’s start with the first one. It consists of the following elements:

  1. Exploration Name
  2. Dates range
  3. Segments
  4. Dimensions
  5. Metrics

1.1 Exploration Name

Exploration Name allows you to specify the report’s name and save it in Google Analytics 4 to access later. You don’t need to click on any button. GA4 saves the name and the report automatically whenever you exit the report.

1.2. Date ranges

You can use date ranges to extend the dates of your report or limit it to one date. GA4 Exploration allows you to see the data up to yesterday. If you are interested in real-time (today’s data), you should enable BigQuery integration. 

1.3 Segments

The segments feature allows you to select a group of users for the analysis. 

For instance, you can be interested in analysing only traffic of your specific Paid Ads campaigns or in analysing your clients’ first product session (relevant for SaaS and mobile apps). You can use (custom) dimensions and metrics in Google Analytics 4 to create more advanced segments. 

1.4 Dimensions

This section allows you to add as many dimensions as you want. You can use the dimensions to break down your data afterwards or create filters. 

For instance, you can be interested to see how mobile and desktop users’ experience differs by applying “device category” dimension as a breakdown.

1.5 Metrics

Apart from importing and using dimensions, you can also use metrics. The most appropriate metric for this report will be “Active users”, and GA4 uses it by default. You can’t remove this metric. It doesn’t mean you can’t use others, but it’s used across many tools. For instance, you can use “revenue” and see how much revenue you receive from returning and new users. 

After understanding the first part of the report, let’s look at the second.

Report part #2 – Tab Settings

GA4 Segment Overlap Parts

The second section of the segment exploration report is “Tab Settings”. It consists of the following sections:

  1. Technique
  2. Segment
  3. Breakdowns
  4. Values
  5. Filters

Let me explain each of them to you.

2.1 Technique

This feature could be more helpful and can be used to jump from one report to another of Google Analytics 4 Explore functionality. Although I rarely use it, I will use this to remind you that you can learn about other GA4 explore reports in these articles:

  1. Free form Exploration
  2. Funnel Exploration
  3. Path Exploration
  4. Cohort Exploration
  5. User Explorer
  6. User Lifetime 

2.2 Segment

This is where you apply the segment you created in section 1.3. To apply the segment, you should drag and drop it from section 1.3 to section 2.2. Remember that segments in this report are the most crucial aspect.

2.3 Breakdowns

As mentioned in 1.3, you can add dimensions to break down your exploration data. 

For instance, you can break it down by device category. To do that, you can drag “device category’ from the dimensions and drop it in the breakdown. You can use any other imported dimension for the breakdown.

You can also use “show rows” to see TOP10, TOP25 and up to 500 rows of your dimension. So you can regulate how much data you want to see and from which position to show with the “Start row”. 

2.4 Values

This section allows you to add more values because “Active users” value is enabled by default and can’t be removed. You can use metrics such as Transactions, Purchase Revenue, Event count, etc. 

2.5. Filters

If you want to see the US traffic only, you can create a segment and apply it, or you can use “country” dimension and use it to create a filter. “Country” doesn’t equal “United States”. Both options are possible and valuable.

Report part #3 – Report View

GA4 Segment Overlap Parts

There are a few things left to discuss. The third part of the report is “Report View”. This window presents the final data after applying filters, segments, breakdowns, and other settings. 

3.1 Right-side menu – Plus icon

This icon allows you to create and include more reports in your exploration report.

3.2 Left-side menu – Undone, Re-do, Share

You can use the left-side menu to share a report with your peers. The share functionality allows you to share the report in read-only mode. You can also export your report in CSV, PDF and as an image.  You can also undo or redo the latest changes you made. 

3.3 Report Navigation

Segment Overlap Desktop and Mobile Users
Segment Overlap Desktop and Mobile Users

If you mouse over the circles, it will be highlighted, and you will see a small pop-up with the metrics and segment information. You can click on the right button of the mouse on any segment ( circles part) to “create a segment from selection”.  

When you create a segment, you can click on “build an audience”, and you can use this audience in Google Ads.

Also, you can click on “View users” to analyse the specific group of users in User Exploration report

Create a segment from selection or View Users Popup
Create a segment from selection or View Users

At the beginning of this section, our goal was to find users who accessed our Merchandise store using desktop and mobile devices, and we nicely accomplished that. 

GA4 Segment Overlap limitations

As with any report in Google Analytics 4, there are limitations that you should be aware of. In our case, they are the following ones:

  1. The main limitation is that you can use up to 3 segments for the report. I would appreciate it if we could use up to 5 segments. Sometimes 3 segments are not enough to see the relevant stats.
  2. The second limitation is that you can add up to 10 metrics in the Segment Overlap report. I couldn’t find myself limited due to that, in any case.

There also needs to be clarity on whether this report uses user_id. Unfortunately, the official Google documentation doesn’t cover it. 


Segment Overlap is an excellent new feature available in Google Analytics 4. You can compare up to 3 segments and see how they overlap. You can dive deeper using other GA4 Explore reports.

The Segment Overlap report interface allows us to use dimensions to break down data and apply filters to see the specific users.

When you find anything valuable and want to share it with your colleagues, you can share it in read-only mode or export it as CSV or PDF.

If you find anything that wasn’t mentioned in this post but would like to see, please let me know in the comment section below. I will appreciate some gratefulness as well 🙂 

Frequently Asked Questions

What’s Segment Overlap report in GA4?

Segment Overlap report allows you to compare up to 3 segments and see if they overlap between themselves. 

When should I use Segment Overlap report in GA4?

You can use it to understand the relationship between multiple groups of your users. For instance, you can use it to see how many users accessed your website on two devices. 

How many segments can I compare in GA4 Segment Overlap?

You can compare up to 3 segments.

What are the limitations of GA4 Segment Overlap?

There are two limitations of Segment Overlap in GA4:
1. You can use up to 3 segments
2. You can add up to 10 metrics

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