How to Fix Website CLS and Improve Core Web Vitals

Understanding Core Web Vitals and CLS

Before diving into fixing CLS, it’s essential to understand what Core Web Vitals are. These metrics evaluate the loading performance, interactivity, and visual stability of a page:

• Largest Contentful Paint (LCP): Measures loading performance. A good LCP is 2.5 seconds or less.
• First Input Delay (FID): Measures interactivity. A good FID is less than 100 milliseconds.
• Cumulative Layout Shift (CLS): Measures visual stability. A good CLS score is less than 0.1.

While LCP and FID are crucial for assessing loading and interaction, CLS focuses on the stability of elements on a webpage during loading. If elements shift unexpectedly (e.g., buttons or images jumping around), it can frustrate users and lead to a negative experience.

A low CLS score indicates that a page remains stable during loading, ensuring that users have a smoother and more predictable experience. For SEO, Google views CLS as a crucial part of page experience, so improving it can have a positive impact on your rankings.

What is CLS and Why Does It Matter?

Cumulative Layout Shift (CLS) refers to the unexpected shifting of content during page loading. For example, imagine you're reading an article, and suddenly an ad or image moves the text you’re reading. This abrupt change can lead to misclicks, frustration, and an overall poor user experience. A high CLS score indicates that users are experiencing these unexpected shifts, which can result in increased bounce rates, lower engagement, and ultimately, a decline in search engine rankings.

A low CLS score indicates that a page remains stable during loading, ensuring that users have a smoother and more predictable experience. For SEO, Google views CLS as a crucial part of page experience, so improving it can have a positive impact on your rankings.

How to Identify CLS Issues

To fix CLS, you need to first identify where the layout shifts are occurring on your website. There are a few methods you can use:

• Google PageSpeed Insights: This tool provides a comprehensive report on Core Web Vitals, including CLS. It identifies issues and gives actionable recommendations.
• Lighthouse Report: Lighthouse is a developer tool built into Chrome that helps you run performance audits, including Core Web Vitals and CLS metrics.
• Web Vitals Extension: The Web Vitals Chrome extension allows you to monitor your website's Core Web Vitals in real-time.
• Chrome DevTools: You can use Chrome's built-in developer tools to analyze layout shifts directly in the browser.

Once you’ve identified the CLS issues, you can move on to fixing them.

Steps to Fix CLS Issues

Here are practical steps you can take to reduce CLS and improve your website's overall stability:

Specify Size for Images and Videos

One of the most common causes of CLS is images and videos that don’t have their dimensions specified. When these elements are loading, they can cause layout shifts if their dimensions aren’t known in advance. To fix this, always specify the width and height for images and videos.

How to fix:

• Add explicit width and height attributes to tags.
• Use CSS to set a container with fixed dimensions to accommodate the image or video.

For example, instead of relying on the browser to figure out the size of an image:

This ensures the space is reserved before the image loads, preventing layout shifts.

Reserve Space for Ads and Embeds

Third-party ads, embedded content, and dynamic elements can cause significant layout shifts if they load asynchronously. If an ad or embedded content doesn’t have a specified size, it might push content down as it loads, causing a visible shift.

How to fix:

• Always specify the size for ads, iframes, and other dynamic content.
• You can use a with a fixed height and width to create a placeholder for the ad or embed. This will help maintain the layout until the content is fully loaded.

Use Font Loading Strategies

Fonts that load late can cause text to reflow once they’re fully loaded, contributing to CLS. This happens when a fallback font is initially displayed and then replaced by the correct font.

How to fix:

• Use in your CSS to ensure that text is displayed with a fallback font until the custom font has loaded. This eliminates the reflow problem.

Avoid Inserting Content Above Existing Content

Avoid dynamically inserting content above existing content, as this can cause shifts. For example, adding a notification banner or alert at the top of the page can push down the page, disrupting the user’s view.

How to fix:

• Add banners or popups in fixed positions or use JavaScript to show them after the page has loaded, not before.
• If content must be inserted dynamically, ensure it’s done in a way that doesn’t affect the flow of the page.

Optimize CSS and JavaScript

Large or blocking CSS and JavaScript files can delay the rendering of content, leading to layout shifts. Optimizing these resources can help reduce this issue.

How to fix:

• Minify CSS and JavaScript to reduce their size.
• Use asynchronous or deferred loading for non-essential JavaScript.
• Split large CSS files into smaller, critical CSS chunks to avoid blocking the render.

Implement a Responsive Design

Responsive websites adapt to different screen sizes, but improper scaling or layout issues on smaller screens can contribute to CLS.

How to fix:

• Ensure your website is designed with a responsive layout that adapts smoothly across devices and screen sizes.
• Test the website on multiple devices to ensure no layout shifts occur when resizing.

Monitor CLS Regularly

Fixing CLS issues isn’t a one-time task. As you continue to add content or make changes to your website, new CLS problems can arise. Regular monitoring is necessary to maintain optimal performance.

How to fix:

• Use tools like Google Analytics, PageSpeed Insights, and the Web Vitals Extension to keep track of your CLS scores.
• Schedule regular performance audits to identify and address potential layout shifts.

Conclusion

Fixing CLS and improving Core Web Vitals is crucial for providing a better user experience, enhancing your website’s SEO Services and boosting engagement. By following the steps outlined above, you can reduce layout shifts, improve the stability of your website, and create a more pleasant browsing experience for your users.

Remember, optimizing Core Web Vitals is an ongoing process. Stay on top of performance issues, monitor your metrics, and continually test for improvements to ensure that your site remains fast, stable, and user-friendly.