How To Improve Your Cumulative Layout Shift on WordPress In 2024

Introduction

What Is Cumulative Layout Shift (CLS)?

Cumulative Layout Shift (CLS) is a metric that measures the unexpected movement of elements on your webpage while it’s loading. Imagine you’re browsing a site on your mobile device and, just as you’re about to click a button or read a piece of content, it suddenly shifts down or to the side. That’s a layout shift, and it can be frustrating for users. CLS quantifies this instability, with lower scores indicating a more stable and user-friendly experience.

Why Is a Good Cumulative Layout Shift Important?

A good CLS score is essential for several reasons. First, it enhances user experience by ensuring that your website’s content remains stable and predictable, making it easier for users to engage with your site. A poor CLS score can lead to frustrated users abandoning your website, which can hurt your conversion rates.

Second, search engines like Google consider CLS when ranking websites, so a better score can improve your site’s search engine optimization (SEO). As a rule of thumb, a CLS score of 0.1 or less is considered excellent, while anything above 0.25 needs improvement.

How Do I Optimize My Cumulative Layout Shift On WordPress?

WordPress sites can suffer from poor CLS scores due to various factors, such as slow-loading images, unoptimized web fonts, inconsistent ad placement, and inefficient use of CSS and JavaScript. For example, if you’ve added a large, high-resolution image to your site without optimizing it, it may take longer to load, causing the surrounding content to shift as the image finally appears.

Why Cumulative Layout Shift Is Important for SEO

Optimizing your WordPress site’s CLS score is crucial for creating a seamless and enjoyable user experience, which can ultimately increase user engagement, conversions, and your site’s visibility in search engine results. By following best practices for CLS optimization, you’ll make your website more accessible and user-friendly, while also boosting its SEO performance.

How To Find Your Cumulative Layout Shift Score

Tools for Measuring Your Cumulative Layout Shift

Google PageSpeed Insights

Google PageSpeed Insights is a fantastic tool for analyzing your website’s CLS score and overall performance. Simply enter your site’s URL, and the tool will provide you with a comprehensive report, including your CLS score and suggestions for improvement. It’s a great starting point to identify areas where your WordPress site may be underperforming.

Lighthouse

Lighthouse is another excellent tool for measuring your site’s CLS score. It’s an open-source tool developed by Google and integrated into Chrome DevTools, but you can also use it as a standalone application or a Node module. Lighthouse provides a detailed performance audit, including your CLS score and other important metrics, along with actionable recommendations to improve your website’s performance.

Chrome DevTools

Chrome DevTools is a suite of web development and debugging tools built into the Google Chrome browser. You can use DevTools to measure your site’s CLS score and gather valuable insights into your site’s performance. To access DevTools, simply open your site in Chrome, right-click anywhere on the page, and select “Inspect.” Then, navigate to the “Performance” tab and click “Start profiling and reload the page.” Once the recording is complete, you’ll see your CLS score and other performance metrics.

Identifying Cumulative Layout Shift issues

Analyzing the report

After using one of the tools mentioned above to measure your CLS score, you’ll receive a report highlighting specific issues that are causing layout shifts on your site. These issues may include images without dimensions, unoptimized web fonts, or dynamic content like ads and embedded videos. Carefully review the report to identify the problem areas that need attention.

Finding the elements causing layout shifts

To pinpoint the exact elements causing layout shifts, you can use Chrome DevTools. Open DevTools and navigate to the “Experience” tab under the “Performance” panel. Here, you’ll find a list of layout shifts that occurred during the recording. Click on a layout shift event to see which elements on your webpage contributed to the shift. This information will help you address the issues and improve your site’s CLS score.

By measuring your CLS score and identifying the specific elements causing layout shifts, you can start optimizing your WordPress site for a better user experience and improved SEO performance.

Optimizing Images and Media

Properly Sizing Images

Image optimization tools

Optimizing your images is essential for improving your site’s CLS score, as large, unoptimized images can cause significant layout shifts. Tools like ShortPixel and Smush can help you compress and resize your images without compromising their quality.

For example, if you have a high-resolution image that’s 2000px wide but only displayed at 800px on your site, these tools can automatically resize it to reduce its file size and improve loading times.

Responsive Image Techniques

Implementing responsive images is another great way to minimize layout shifts. WordPress has built-in support for responsive images, which means it automatically serves the most appropriate image size based on the user’s device and screen size.

To make the most of this feature, ensure that you’re uploading images with multiple sizes (e.g., thumbnail, medium, large) and using the “srcset” attribute in your image tags. WordPress should handle this automatically, but if you’re looking to highly optimize your images, or if you’re working on developing a theme, doing this manually can be beneficial.

Implementing lazy loading

Native Lazy Loading

Lazy loading is a technique that defers the loading of images and other media until they’re about to enter the user’s viewport. This can significantly improve your site’s CLS score by reducing layout shifts caused by slow-loading media. One way to implement lazy loading is by using the native “loading” attribute, which is supported by modern browsers. Simply add the “loading=lazy” attribute to your image and iframe tags to enable lazy loading.

Lazy Loading Plugins

If you prefer a more automated approach, you can use a WordPress plugin like a3 Lazy Load or Smush to implement lazy loading on your site. These plugins work out of the box, meaning you don’t need to manually add any attributes to your image tags. Just install the plugin, configure the settings, and your site’s images and media will be lazy-loaded automatically.

Using proper aspect ratios for media

Importance of Aspect Ratio Consistency

Ensuring consistent aspect ratios for your images and videos is crucial for preventing layout shifts. When media elements have varying aspect ratios, they can cause the surrounding content to shift as they load. Maintaining consistent aspect ratios helps to avoid this issue and improves your site’s CLS score.

Calculating and Specifying Aspect Ratios for Images and Videos

To maintain consistent aspect ratios, first calculate the ratio by dividing the media’s height by its width. For example, if an image has a width of 800px and a height of 600px, its aspect ratio is 3:4. Once you have the aspect ratio, use CSS to specify the dimensions of the media element’s container. This ensures that the space is reserved for the media before it loads, preventing layout shifts. For example, you can use the “padding-top” property with a percentage value to set the aspect ratio of a container:

.image-container {
    position: relative;
    width: 100%;
    padding-top: 75%; /* 3:4 aspect ratio */
}

By optimizing your images, implementing lazy loading, and maintaining consistent aspect ratios for your media, you can significantly improve your WordPress site’s CLS score and enhance the overall user experience.

Managing Fonts and Styling

Optimize Web Font Loading

Using Preconnect and Preload

Web fonts can cause layout shifts if they’re not optimized correctly, as they can block rendering until they’re fully loaded. To improve font loading performance, you can use the “preconnect” and “preload” techniques. “Preconnect” establishes an early connection to the font provider, while “preload” fetches the font files ahead of time. For example, if you’re using Google Fonts, you can add the following code to your site’s <head> section:

<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link rel="preload" as="style" href="https://fonts.googleapis.com/css?family=Roboto&display=swap">

Choosing Efficient Font Formats

Another way to optimize web font loading is by selecting efficient font formats. Web Open Font Format 2 (WOFF2) is a modern, compressed font format that provides faster loading times compared to older formats like TTF or OTF. When using web fonts, ensure you’re using WOFF2 files for the best performance.

Eliminating Flash of Unstyled Text (FOUT) and Flash of Invisible Text (FOIT)

Using font-display CSS Property

FOUT and FOIT occur when a browser displays a fallback font or hides the text entirely while waiting for the web font to load, which can cause layout shifts. To prevent this, you can use the “font-display” CSS property. The “font-display: swap;” value tells the browser to use the fallback font immediately and swap it with the web font once it’s loaded. Add this property to your `@font-face` declaration in your CSS:

@font-face {
    font-family: 'Roboto';
    src: url('path/to/Roboto.woff2') format('woff2');
    font-display: swap;
}

Self-Hosting Fonts or Using a Fast Font Provider

Self-hosting fonts can help minimize layout shifts by reducing the number of external resources your site needs to fetch. Download the font files (preferably in WOFF2 format), upload them to your server, and reference them in your CSS using the `@font-face` declaration.

Alternatively, use a fast font provider like Google Fonts to ensure quick font delivery.

By optimizing web font loading and eliminating FOUT and FOIT, you can prevent layout shifts caused by fonts and further improve your site’s CLS score. This not only enhances user experience but also makes your site visually consistent and professional.

Handling Ads and Dynamic Content

Reserving Space for Ads and Iframes

Importance of Reserved Space

Ads and dynamic content like embedded videos or social media widgets can cause layout shifts if they don’t have a reserved space on your webpage. Without reserved space, these elements can push down or reposition surrounding content as they load, negatively impacting your site’s CLS score. Reserving space for ads and iframes ensures a more stable layout and a better user experience.

Techniques for Reserving Space

To reserve space for ads and iframes, you can use CSS to create a container with a fixed size or aspect ratio. For example, if you have an ad that’s 300px wide and 250px tall, you can create a container with those dimensions:

.ad-container {
    width: 300px;
    height: 250px;
}

For dynamic content with varying dimensions, like responsive ads or embedded videos, you can use the aspect ratio technique mentioned in Section 3:

.video-container {
    position: relative;
    width: 100%;
    padding-top: 56.25%; /* 16:9 aspect ratio */
}

Avoiding ad reflow

What Is Ad Reflow?

Ad reflow occurs when an ad loads and resizes itself after the page has rendered, causing layout shifts. This is a common issue with dynamically sized ads, and it can significantly affect your site’s CLS score.

Preventing Ad Reflow

To prevent ad reflow, you can use a combination of techniques. First, reserve space for ads as described above. Second, avoid using dynamically sized ads that change dimensions after the page has loaded.

Instead, choose fixed-size ads or responsive ads that adapt their dimensions to the reserved space. Finally, consider implementing ad refresh techniques that don’t cause layout shifts, such as using an ad refresh API or reloading ads within their reserved space.

By reserving space for ads and iframes and preventing ad reflow, you can reduce layout shifts caused by dynamic content and improve your WordPress site’s CLS score. This ensures a more stable browsing experience for your users and can lead to increased engagement and conversions.

Minimizing CSS and JavaScript Impact on Layout Shifts

Inline Critical CSS

What Is Critical CSS?

Critical CSS refers to the minimum set of CSS rules required to render the above-the-fold content of your webpage. Inlining critical CSS means embedding these rules directly in your site’s HTML, so they’re loaded as quickly as possible. This helps prevent layout shifts caused by slow-loading external stylesheets.

Extracting and Inlining Critical CSS

To extract critical CSS, you can use tools like Critical or PurifyCSS. These tools analyze your site’s HTML and CSS files and generate a smaller CSS file containing only the rules needed to render above-the-fold content. Once you have the critical CSS, you can inline it by adding a `<style>` tag with the critical CSS rules in your site’s `<head>` section:

<head>
...
    <style>
        /* Critical CSS rules */
    </style>
...
</head>

Defer Non-Critical CSS and JavaScript

Importance of Deferring Non-Critical Resources

Non-critical CSS and JavaScript are resources that don’t affect the initial rendering of your webpage. Deferring these resources means delaying their loading until the critical resources have been loaded. This can help reduce layout shifts by ensuring that your page’s layout is stable before any non-critical scripts or styles are applied.

Techniques for deferring CSS and JavaScript

To defer non-critical CSS, you can use the “media” attribute with a temporary value and then change it back using JavaScript once the page has loaded. For example:

<link rel="stylesheet" href="path/to/non-critical.css" media="print" onload="this.media='all'">
<noscript><link rel="stylesheet" href="path/to/non-critical.css"></noscript>

For deferring non-critical JavaScript, you can use the “defer” attribute in your script tags:

<script src="path/to/non-critical.js" defer></script>

By inlining critical CSS and deferring non-critical CSS and JavaScript, you can minimize the impact of these resources on layout shifts and improve your site’s CLS score. This ensures a faster and more stable rendering of your WordPress site, contributing to a better user experience and higher search engine rankings.

Leveraging Critical Rendering Path Optimization for Better CLS

Understanding the Critical Rendering Path

The critical rendering path (CRP) refers to the sequence of steps a browser takes to process and render the HTML, CSS, and JavaScript of a web page. Optimizing the CRP ensures that your site’s content is displayed as quickly as possible, which can help minimize layout shifts and improve your site’s CLS score.

When the CRP is optimized, your site’s content is rendered more efficiently, reducing the likelihood of elements loading slowly or out of order. This can help prevent unexpected layout shifts and contribute to a better user experience.

Minimizing Render-Blocking Resources

Render-blocking resources are files, such as CSS and JavaScript, that must be loaded before the browser can render the page. By minimizing or deferring the loading of these resources, you can optimize the CRP and reduce layout shifts.

Techniques for Minimizing Render-Blocking Resources

Some methods for minimizing render-blocking resources include:

• Inlining critical CSS: Include only the essential CSS needed to render the above-the-fold content directly in the HTML file, reducing the need for additional requests.
• Deferring non-critical CSS and JavaScript: Use the `async` or `defer` attributes for non-critical scripts and the `media` attribute for non-critical CSS files to ensure they are loaded after the initial rendering.

Optimizing the Order of Page Resources

The order in which page resources are loaded can affect the CRP and your site’s CLS score. By optimizing the order of resources, you can ensure that critical content is loaded first, reducing the chances of layout shifts.

Some strategies for optimizing the order of page resources include:

• Loading critical content first: Prioritize the loading of essential content, such as above-the-fold images and text, to ensure that users see meaningful content as quickly as possible.
• Using the `preload` attribute: Apply the `preload` attribute to critical resources, such as fonts or images, to tell the browser to download them as early as possible.

By leveraging critical rendering path optimization, you can improve your site’s CLS score and overall performance. Techniques like minimizing render-blocking resources, and optimizing the order of page resources can contribute to a more stable and enjoyable browsing experience for your users, leading to increased user engagement, higher search engine rankings, and a more successful WordPress site.

Optimizing Server Performance for Better CLS

Importance of Server Performance

Connection Between Server Performance and CLS

Your server’s performance can have a significant impact on your site’s CLS score. A fast and responsive server can deliver content quickly, helping to reduce layout shifts caused by slow-loading elements. Additionally, server optimization can improve the overall performance of your site, contributing to a better user experience and higher search engine rankings.

Upgrading Your Hosting Plan

Assessing Your Current Hosting Situation

Examine your current hosting plan to determine if it’s sufficient for your site’s needs. If your site is experiencing slow loading times or frequent downtime, it may be time to consider upgrading to a more powerful hosting plan or switching to a new hosting provider.

Choosing a Suitable Hosting Plan

When selecting a hosting plan, consider factors like server resources, scalability, and support for performance-enhancing features. For example, a managed WordPress hosting plan might offer better performance optimization, faster servers, and dedicated support, which can contribute to improved server performance and a lower CLS score.

Implementing Server-Level Caching

Benefits of Server-Level Caching

Server-level caching involves storing a version of your site’s content on the server, allowing it to be delivered quickly to users without needing to generate the content for each request. This can significantly improve your site’s loading speed and overall performance, which can help reduce layout shifts and improve CLS.

Configuring Server-Level Caching

To enable server-level caching, you may need to access your server’s configuration files or use a control panel provided by your hosting provider. Popular server-level caching solutions include Varnish and Nginx. Consult your hosting provider’s documentation or support team for guidance on implementing server-level caching for your WordPress site.

Optimizing Your Server’s Database

Importance of Database Optimization

A well-optimized database can contribute to a faster and more responsive WordPress site, helping to minimize layout shifts caused by slow-loading content. Regularly optimizing your site’s database can improve server performance and ensure that your site’s data is efficiently managed.

Techniques for Database Optimization

Some methods for optimizing your server’s database include:

• Cleaning up and removing unnecessary data, such as old revisions, spam comments, and expired transients.
• Repairing and optimizing database tables using tools like phpMyAdmin or a WordPress plugin like WP-Optimize.
• Ensuring that your database is using the appropriate character set and collation for your site’s language and region.

By focusing on server optimization and implementing strategies like upgrading your hosting plan, enabling server-level caching, and optimizing your server’s database, you can improve your site’s CLS score and overall performance. These optimizations contribute to a better user experience and can lead to increased user engagement, higher search engine rankings, and a more successful WordPress site.

Implementing a Content Delivery Network (CDN)

Benefits of Using a CDN

A Content Delivery Network (CDN) is a system of distributed servers that deliver content to users based on their geographic location. By using a CDN, you can improve your site’s loading speed, reduce server load, and enhance user experience. A faster-loading site is less likely to experience layout shifts, which can contribute to a better CLS score.

Choosing a CDN for your WordPress site

Many CDN providers are available, with popular options like Cloudflare, Fastly, and Amazon CloudFront. Choose a CDN that fits your needs and budget, and follow their setup instructions to integrate the CDN with your WordPress site.

Monitoring and Maintaining CLS Performance

Regularly Monitoring CLS Scores

Importance of continuous Monitoring

Regularly monitoring your CLS scores is crucial for maintaining optimal performance and user experience on your WordPress site. Site changes, plugin updates, and new content can introduce new layout shift issues, so it’s essential to keep an eye on your CLS score and address any problems promptly.

Tools for Continuous Monitoring

To monitor your CLS scores regularly, you can use tools like Google PageSpeed Insights, Lighthouse, and Chrome DevTools, as mentioned in Section 2. By running periodic tests, you can keep track of your site’s performance and ensure that your CLS score remains within the acceptable range.

Staying Up-To-Date With Best Practices

Importance of keeping up with industry trends

Web development is a constantly evolving field, and new techniques and best practices are continually emerging. Staying up-to-date with the latest developments in performance optimization, web design, and WordPress can help you maintain and even improve your site’s CLS score and overall performance.

Following Industry Resources

To stay informed about the latest best practices, follow industry blogs, podcasts, and social media accounts. Some excellent resources include CSS-Tricks, Smashing Magazine, and the official WordPress blog. By learning from experts and implementing new techniques, you can keep your site’s performance at its best and provide an exceptional user experience.

Regularly Auditing and Optimizing Your Site

Importance of Site Audits

Conducting regular site audits is vital for maintaining optimal CLS performance. A comprehensive site audit can help you identify issues, such as outdated plugins, inefficient code, or improperly sized images, that may be affecting your site’s CLS score.

Techniques for Site Audits and Optimization

To perform a site audit, you can use tools like Lighthouse and Chrome DevTools to analyze your site’s performance and uncover any issues. After identifying problem areas, you can then optimize your site by implementing the strategies discussed in this outline, such as optimizing images, managing fonts, and reserving space for dynamic content.

By regularly monitoring and maintaining your site’s CLS performance, you can ensure a stable and enjoyable browsing experience for your users. This not only contributes to higher user engagement and conversions but also improves your site’s search engine rankings, making your WordPress site more successful in the long run.

Implementing a Performance-First Mindset

Prioritizing Performance From the Beginning

Importance of a Performance-First Approach

Adopting a performance-first mindset is essential for creating and maintaining a fast, efficient, and user-friendly WordPress site. Prioritizing performance from the beginning ensures that your site is built on a strong foundation, making it easier to maintain and optimize for CLS and other performance metrics.

Building with Performance in Mind

When developing your site, consider the impact of each element on your site’s performance. For example, when selecting a theme, opt for a lightweight, well-coded option that prioritizes performance. Likewise, when choosing plugins, favor those with minimal performance overhead and avoid installing too many plugins, as they can slow down your site and cause layout shifts.

Educating and Involving Your Team

Importance of Team Education

Ensuring that your entire team understands the importance of performance and the best practices for optimizing CLS is crucial for maintaining a high-performing WordPress site. By educating your team, you can create a culture that values performance and continually works towards improving your site’s user experience.

Encouraging team collaboration

Involve your team in performance-related discussions and decision-making. Encourage designers, developers, content creators, and other team members to collaborate and share their expertise to develop efficient solutions. For instance, designers can create layouts with CLS in mind, while content creators can optimize their images and adhere to proper aspect ratios.

Continuously refining and improving your site

Importance of Ongoing Optimization

A performance-first mindset requires continuous refinement and improvement. As your site evolves, new content is added, and plugins are updated, it’s essential to reassess your site’s performance and make necessary optimizations to maintain or improve your CLS score.

Regularly reassessing your site’s performance

Periodically review your site’s CLS scores and other performance metrics, and identify any areas that need optimization. This might include updating your theme or plugins, optimizing new content, or refining your site’s design. By continually refining and improving your site, you can ensure it remains fast, efficient, and user-friendly.

Implementing a performance-first mindset is key to achieving and maintaining optimal CLS scores on your WordPress site. By prioritizing performance from the start, educating and involving your team, and continuously refining and improving your site, you can create a high-performing website that offers an exceptional user experience and ranks well in search engines.

Understanding the Broader Context of Web Vitals

Importance of Core Web Vitals

Comprehensive Performance Assessment

While optimizing your site’s Cumulative Layout Shift is essential, it’s important to remember that CLS is just one of the Core Web Vitals metrics. To comprehensively assess your site’s performance, you should also consider optimizing for the Time To First Byte (TTFB), First Contentful Paint (FCP), Largest Contentful Paint (LCP), First Input Delay (FID), and Total Blocking Time (TBT). Focusing on all three metrics ensures that you’re providing a well-rounded, exceptional user experience.

Impact on Search Engine Rankings

Google uses Core Web Vitals as a ranking factor in its search algorithm, which means that optimizing for all three metrics can improve your site’s search engine visibility. By addressing these other metrics alongside CLS, you can increase your chances of ranking higher in search results and attracting more organic traffic to your WordPress site.

Conclusion

In conclusion, improving your Cumulative Layout Shift on WordPress is crucial for providing an exceptional user experience, boosting search engine rankings, and increasing user engagement. To achieve a better CLS score, implement the following strategies:

1. Optimize your images and use responsive design techniques to ensure that your site adapts to different devices and screen sizes.
2. Choose the right WordPress theme and plugins that prioritize performance and minimal layout shifts.
3. Optimize your site’s CSS and JavaScript, minimizing render-blocking resources, and deferring non-critical assets.
4. Minimize the use of web fonts or optimize their loading to prevent layout shifts caused by font swapping.
5. Use placeholders and skeleton screens to ensure that users see a stable layout as the page loads.
6. Manage animations and transitions carefully, ensuring that they don’t cause unexpected layout shifts.
7. Optimize your server performance by upgrading your hosting plan, implementing server-level caching, and optimizing your server’s database.
8. Leverage critical rendering path optimization to minimize layout shifts and improve your site’s overall performance.
9. Regularly audit your site’s performance using tools like Google PageSpeed Insights, Lighthouse, and WebPageTest to identify and fix issues related to CLS.
10. Understand the broader context of Web Vitals, focusing on all Core Web Vitals metrics (including TTFB, CLS, LCP, FID, and TBT) to create a well-rounded, high-performing WordPress site.

By following these guidelines and continuously monitoring your site’s performance, you can create a stable, fast, and enjoyable browsing experience for your users. Remember, a better CLS score contributes to a successful WordPress site, leading to increased user engagement and higher search engine rankings. Happy optimizing!