Understanding and Fixing Cumulative Layout Shift (CLS) Issues

 

Cumulative Layout Shift (CLS) is one of the key performance metrics that affect how users interact with a website. In simple terms, CLS refers to the unexpected movement of web elements during page loading. This can happen when images, buttons, or blocks of text shift around as the page is being rendered. Such shifts frustrate users because they may click on the wrong thing or lose track of what they were reading. This blog explains what causes CLS, why it matters, and practical steps to fix these issues for a smoother browsing experience.

What is Cumulative Layout Shift (CLS)?

CLS measures the visual stability of a webpage. It tracks how much the layout of a page moves around after its initial load. Each time an element shifts unexpectedly, it adds to the overall CLS score. A high CLS score indicates that a website has a lot of layout shifts, which can lead to poor user experience. Web developers must work to keep this score low to ensure that pages are stable as they load.

Why Does CLS Matter?

A stable webpage is essential for good user experience. When a website loads without shifting elements, it feels more reliable and easier to interact with. Research shows that pages with a high CLS score tend to have higher bounce rates. Visitors are less likely to stay on pages that cause them to lose their place while reading or navigating. In addition, search engines consider page speed and stability as important factors in search rankings. Therefore, reducing CLS not only improves user satisfaction but also helps boost the website's performance in search results.

Common Causes of CLS

There are several reasons why a webpage might experience layout shifts. One common cause is the improper loading of images and videos. If dimensions are not set or if lazy loading is not correctly implemented, these elements may load at different speeds and push other content out of place. Similarly, ads that load asynchronously or dynamically can shift content as they appear. Fonts also can contribute if web fonts take too long to load and then replace system fonts, causing text to jump. Understanding these causes is the first step in addressing CLS.

How to Measure CLS

Measuring CLS is simple with the tools available today. Google’s Lighthouse and PageSpeed Insights provide a CLS score for your webpages. These tools break down which elements are causing layout shifts. By reviewing these reports, developers can pinpoint specific issues. Monitoring the CLS score regularly is important because even small changes to the layout or the addition of new content can affect stability.

Effective Strategies to Reduce CLS

The goal is to keep your pages as stable as possible from the moment they start loading until the entire page is rendered. Here are some practical strategies:

1. Minimize Layout Changes

Set fixed dimensions for images, videos, and other elements. This ensures that the space required for these items is allocated before they load. Consistent sizing prevents the page from shifting unexpectedly.

2. Optimize Ad Placement

Ads often load at different speeds than main content. Reserve space for them in your design. This can be achieved by specifying the size of ad containers so that when an ad loads, it does not push other elements down or sideways.

3. Improve Font Loading

Implement strategies that allow fallback fonts to be used immediately. In your CSS, add rules that display fallback fonts until the custom fonts load. This avoids the sudden shift in text appearance once the custom font is applied.

4. Use Efficient Caching and CDNs

By serving your site’s assets from servers that are geographically closer to your users, you reduce load times. While this does not directly affect CLS, faster loading can contribute to a more stable rendering of elements on your pages.

5. Streamline Third-Party Scripts

Third-party scripts, such as those used for ads or social media embeds, can cause sudden shifts. Evaluate their necessity and load them in a way that minimizes impact, such as deferring their load until after the main content is displayed.

The Role of Expert Developers

If you encounter persistent issues with layout shifts, it is wise to consult professionals. A skilled website designing company in India can conduct detailed audits of your site and implement fixes that keep your CLS score low. Working with experienced developers ensures that changes are implemented safely and effectively.

In addition, many businesses rely on expert advice to manage site performance. At times, even small adjustments can make a significant difference in how stable a site feels to visitors.

Final Thoughts

Ensuring that a website loads smoothly with minimal layout shifts is key to creating a friendly user experience. By addressing problems with images, ads, fonts, and third-party scripts, you can reduce the CLS score and provide a more stable browsing experience. The steps outlined above can help even those new to web performance optimization to make meaningful improvements. Remember, every small change can have a big impact on user satisfaction and search engine rankings. With proper strategies and expert guidance, your website can perform better and leave a lasting, positive impression on visitors.