Understanding how users engage with your content is critical to optimising performance, especially in content-rich or conversion-focused experiences. Scroll depth tracking provides powerful behavioural insight—revealing how far users travel down the page and where they drop off. In Google Analytics 4 (GA4), scroll tracking is available out of the box—but there’s more to it than meets the eye.

In this guide, we’ll walk you through how scroll tracking works in GA4, how to implement it properly, and how to take full advantage of the data to inform UX, content, and conversion strategies.

What Is Scroll Depth Tracking?

Scroll depth tracking measures how far a user scrolls down a page. Unlike Universal Analytics (UA), where you had to set this up manually via Google Tag Manager (GTM), GA4 tracks a scroll event by default when a user reaches 90% of the page height.

However, if you're only relying on this default, you're missing critical visibility. Most digital marketers benefit from granular scroll tracking, capturing additional thresholds such as 25%, 50%, and 75%. This is especially valuable for:

• Content engagement analysis
  
  
• Landing page performance
  
  
• eCommerce product page drop-off
  
  
• Lead form visibility tracking

Step-by-Step Setup: Granular Scroll Depth in GA4 (via GTM)

To go beyond GA4’s default scroll event, you’ll need to configure additional scroll triggers in Google Tag Manager (GTM) and send them as custom events to GA4.

Prerequisites:

• GA4 property configured
  
  
• GTM installed on your site
  
  
• Basic understanding of GTM tag and trigger structure
  
  

1. Create a Scroll Trigger in GTM

1. Go to Triggers > New
   
   
2. Choose Scroll Depth as the trigger type
   
   
3. Configure as follows:
   
   
   
   • Vertical Scroll Depths: Enter 25,50,75
     
     
   • Check "All Pages" or specify a subset using conditions
     
     
   • Name it: Scroll Depth Trigger (25/50/75)
     
     

Note: GA4's built-in scroll event fires at 90%, so we exclude that from this trigger to avoid duplication.

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2. Create a GA4 Event Tag

1. Go to Tags > New
   
   
2. Choose GA4 Event as the tag type
   
   
3. Select your GA4 Configuration Tag
   
   
4. Enter Event Name: scroll_depth
   
   
5. Under Event Parameters, configure:
   
   
   
   • scroll_percent → {{Scroll Depth Threshold}} (built-in GTM variable)
     
     
   • Optionally add page_location, page_title, or custom dimensions
     
     

These parameters will allow for flexible reporting in GA4.

6. Trigger: Select the Scroll Depth Trigger (25/50/75) created earlier
   
   
7. Save the tag and publish
   
   

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3. Test Using Preview Mode

Before publishing to live, enter GTM’s Preview Mode and confirm:

• Events fire on scroll at 25%, 50%, and 75%
  
  
• Tag is triggered as expected
  
  
• Event shows in the Realtime section of GA4 under scroll_depth
  
  

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4. Configure Custom Dimensions (Optional but Recommended)

To unlock powerful analysis in GA4, configure scroll_percent as a Custom Dimension:

1. In GA4, go to Admin > Custom Definitions
   
   
2. Click Create Custom Dimension
   
   
3. Set:
   
   
   
   • Name: Scroll Percent
     
     
   • Scope: Event
     
     
   • Parameter: scroll_percent
     
     

Now you'll be able to segment and report based on how far users scrolled.

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How to Use Scroll Depth Data in GA4

Once implemented, scroll depth can be visualised in Explorations, or used in:

Funnel Analysis

Track how scroll behavior correlates with key conversions—e.g., form submissions, CTA clicks, or purchases.

Content Performance

Identify blog posts or product pages where users drop off before seeing key content or offers.

CRO Diagnostics

Scroll depth is a strong signal of user interest. Combine it with session duration, exit rates, and click-through data to identify UX friction.

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Going Beyond: Using Scroll Data Strategically

Beyond basic tracking, scroll depth data becomes truly powerful when integrated with your broader marketing strategy. For example, by creating custom audiences based on scroll behaviour—such as users who reach 75% of the page but do not convert—you can build highly relevant remarketing campaigns or trigger on-site personalisation.

We also recommend tailoring your scroll tracking implementation based on page type. Product pages, blog content, and landing pages serve different user intents, so differentiating scroll behaviour across these templates can provide more precise insights.

Finally, scroll data is most effective when combined with other engagement signals. Pair it with metrics like video plays, form starts, or CTA clicks to develop a full-funnel understanding of user behaviour. This layered view allows you to identify high-interest users and surface friction points with far greater clarity—powering more informed optimisation decisions.

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Final Thoughts

GA4’s default scroll tracking is a helpful starting point—but granular scroll depth implementation via GTM unlocks far deeper insight. For digital marketers focused on content engagement, conversion optimisation, or funnel diagnostics, scroll data is an invaluable addition to the analytics stack.

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