Cumulative Layout Shift: A KPI You Can’t Overlook for SEO Success

Is your website suffering from low search rankings, but you can’t pinpoint the problem? Then it might be that your website is having problems loading page elements simultaneously and in a smooth manner. There’s an official score that measures this – Cumulative Layout Shift. 

We’ll go into detail on what this core web vitals metric is all about and how it affects your SEO performance. Therefore, after reading this article, you can formulate a plan of action that will help you optimize your website with this metric in mind and achieve your best search rankings yet.

Below is an illustration that shows how cumulative layout shift interrupts elements' position on a page while they load:

Image Source: Hostinger

What is Cumulative Layout Shift?

Cumulative Layout Shift (CLS) is a metric used in web performance to measure unexpected visual stability issues, particularly as content loads on a webpage. It focuses on how often and how significantly elements shift around as a page loads, thereby impacting the user experience. 

The kind of elements that can cause shifts include:

  • Fonts

  • Videos
  • Contact forms
  • Images
  • Buttons
  • And other forms of content

As an illustration, let’s say you wanted to click the sidebar of a homepage and it shifted upwards. As a result, you accidentally clicked on a newsletter CTA button that popped up. This is an example of a layout shift.

High CLS scores indicate poor user experience, as sudden movements in content can lead to accidental clicks or make it hard for users to interact. Furthermore, CLS is part of Google's Core Web Vitals, which emphasizes loading speed, interactivity, and visual stability as key aspects of site performance. 

To reduce CLS, developers can define size attributes for images, use placeholder elements, and minimize late content injections. Additionally, a low CLS score contributes to better usability and higher search engine rankings.

The Benefits of Optimizing Cumulative Layout Shift for SEO

Are you not sure why it’s worth paying attention to your CLS score when improving your website SEO strategy? The general consensus among SEO professionals is that a lower CLS score leads to higher rankings. In this section, you’ll see why that’s the case and therefore it must  become one of your key performance indicators when building an SEO-friendly website. 

Improved User Experience

Optimizing CLS enhances the user experience by reducing unexpected shifts in a webpage’s content. When elements stay in place as pages load, visitors experience a smoother and more predictable interaction. This reduces frustration caused by accidentally clicking on shifting elements. 

The improved visual stability leads to increased engagement and satisfaction, encouraging users to spend more time on the site. Consequently, Google takes note of this improved website engagement metrics and gives you a boost in the search rankings. 

Furthermore, a positive user experience is not only essential for retaining visitors but also builds trust in the brand, thereby leading to better conversion rates. This is especially true on mobile devices, where layout shifts can be particularly disruptive.

Better Search Engine Rankings

CLS optimization contributes to better search engine rankings as it is a part of Google’s Core Web Vitals, which prioritize performance metrics like load time, interactivity, and visual stability. Overall, Google rewards pages with low CLS scores because they indicate quality and usability. 

Therefore, by improving CLS, sites are more likely to meet Google’s recommended thresholds, resulting in higher rankings in search results. This ranking boost can lead to increased visibility, attracting more organic traffic and ultimately benefiting a website’s overall SEO strategy. 

Increased Engagement and Conversions

Optimizing CLS can lead to increased user engagement and conversion rates, as a stable layout reduces frustrations associated with accidental clicks and interrupted content. Hence,  users are more likely to stay, explore, and complete actions when the content remains visually consistent during loading. 

This stability helps build trust and encourages users to take desired actions. For example, signing up or making purchases, thereby boosting conversion rates. Ultimately, it will lead to better SEO performance since a conversion indicates the page meets the search intent

Reduced Bounce Rates

Minimizing CLS can reduce a site’s bounce rate by providing a smoother and more predictable loading experience. When content does not shift unexpectedly, users are less likely to abandon the page out of frustration. 

This is especially relevant for mobile users, where layout shifts can be more pronounced due to smaller screen sizes. By optimizing CLS, website owners can keep users engaged longer, and in the process, increase the chance they will explore more pages and complete actions. 

A lower bounce rate signals to search engines that a site is valuable and relevant, so it has a positive knock-on effect on your SEO performance. 

Better Analytics Accuracy

Improving CLS also benefits the accuracy of website analytics. When layout shifts cause accidental clicks or unintended interactions, analytics data can become skewed. This misrepresents how users actually engage with the site. 

Therefore, reducing CLS minimizes these unintentional actions, and you’ll receive more accurate insights into user behavior, click-through rates, and navigation patterns. 

With reliable analytics, website owners can make more informed decisions to enhance the site further. Accurate data also helps identify true areas of improvement, ensuring that resources are invested in optimizations that genuinely improve user experience and align with SEO objectives.

What Causes Cumulative Layout Shift Problems?

Now let’s turn our attention towards the various factors that can lead to CLS issues. This will help you understand where you need to be extra careful when building your website. Here are the top factors to consider:

  • Unspecified image dimensions: When image dimensions aren’t defined, browsers can’t allocate space for images in advance. This causes the page to shift as images load, thereby leading to CLS issues. Therefore, setting explicit width and height for images helps reserve space and prevents layout disruptions as content loads. This straightforward fix can significantly reduce visual instability.

  • Late-loading fonts: Fonts loading after content display can lead to "Flash of Unstyled Text" (FOUT) or "Flash of Invisible Text" (FOIT), which causes layout shifts as text re-renders. Hence, web fonts should be optimized for quicker loading or set with fallback fonts to avoid these visual disruptions.
  • Dynamic content injection: Content that loads late, such as ads, pop-ups, or embedded widgets, often causes layout shifts. These elements may push other content around the page, resulting in CLS issues. To mitigate this, reserve space for dynamic content during page design. This planning ensures that late-loading elements don’t disrupt the overall layout.
  • Animations and transitions: Certain animations or transitions, if not handled carefully, can cause layout shifts. For example, expanding banners or modals that shift other elements affect CLS. Also, using CSS animations that don’t push content around, or adding animations that occupy designated space, can prevent such shifts.
  • Ads and embeds without reserved space: Ads and embeds, like iframes, can cause sudden shifts when they load without predefined space. This is particularly common for responsive ads that resize or reposition after loading. Again, allocating space for these elements ahead of time leads to a better user experience.

Best Practices to Reduce Cumulative Layout Shift  

Do you want to start reducing your CLS score to optimize your SEO strategy? Then you’ll love the actionable best practices that will help improve your website loading process to impress customers and search engines alike. 

Use CSS Transformations for Animations

When animations or transitions are required, using CSS transformations like “translate” or “scale” rather than properties like height or width can help reduce CLS. That’s because transformations allow for smooth movements without pushing other elements around.

Furthermore, by avoiding layout-altering animations, visual stability remains intact and provides a consistent user experience. Animations applied in this way keep interactive elements stable, which prevents accidental clicks or disruptions in navigation. 

Define Dimensions for Media Elements

One of the simplest ways to reduce CLS is to specify width and height attributes for images, videos, and other media elements. By setting dimensions, browsers can allocate appropriate space for these elements as the page loads.

For responsive designs, CSS can be used to adjust dimensions based on screen size. This ensures media elements maintain the correct layout across devices. The practice not only reduces visual instability but also contributes to a more seamless and predictable loading experience for users.

Preload Web Fonts

To prevent layout shifts from late-loading fonts, it’s best to preload key web fonts. Font preloading signals the browser to prioritize font loading and that reduces that chance of Flash of Invisible or Unstyled Text. 

Additionally, this ensures that text elements display correctly without sudden shifts when fonts load. You’ll want to set fallback fonts that closely match the intended font’s size and style. This allows you to maintain layout stability, even if the custom font takes time to load. 

Optimize and Test Layout Loading

Testing layout loading performance helps identify and resolve CLS issues before they affect users. Tools like Google’s Lighthouse can measure CLS and provide actionable insights for improvement. During testing, consider factors like device type and connection speed, as layout shifts can vary across conditions. 

You can also use the Hike SEO Analytics module to monitor your website performance and spot potential issues before they get out of hand. 

Frequently Asked Questions

Why does CLS matter for SEO?

CLS directly impacts SEO because it’s a part of Core Web Vitals, which Google uses as a ranking factor. Pages with high CLS scores can lead to a poor user experience, as elements that shift can cause users to accidentally click on the wrong parts of a page. 

Therefore, reducing CLS can help improve search rankings by enhancing the user experience.

How is CLS scored?

CLS scores range from 0.1 (Good) to over 0.25 (Poor). This score is based on elements moving unexpectedly during loading, which impacts the page’s stability. 

Scores in the good range mean fewer disruptive shifts, whereas higher scores indicate a need for improvement to avoid potential SEO and user experience issues.

How do I check my CLS score?

Use tools like Google PageSpeed Insights, Search Console, and Lighthouse in Chrome DevTools to view your CLS score. These tools provide insights into your layout shifts, thereby helping identify and address areas needing improvement. 

You’ll find that regularly monitoring your CLS score allows for proactive adjustments to maintain a stable page layout. 

Do mobile and desktop CLS scores differ?

Yes, CLS can vary between mobile and desktop due to screen size differences and unique loading conditions. That’s because Google’s mobile-first indexing emphasizes the need to optimize CLS across both device types to ensure consistency. 

Therefore, it’s vital to monitor and improve CLS scores on both platforms for a comprehensive user experience.

How often should I check my CLS score?

Monitor CLS scores regularly, and especially after site changes. Also, monthly checks help keep CLS optimized, but more frequent reviews are recommended if there are major design updates. 

Overall, staying on top of CLS ensures you maintain a stable layout, which can improve user satisfaction and minimize SEO risks associated with shifting content.

Hike SEO

Reducing your CLS score can go a long way toward securing the top spots in the SERPs (search engine result pages). It helps achieve your SEO ambitions for a range of target keywords that you might be having trouble with due to fierce competition. 

Don’t forget to apply the best practices for reducing your CLS such as defining the dimension of media elements, using CSS transformation of animations, and preloading fonts. 

Furthermore, your road to SEO success will be much easier with an all-in-one SEO tool on your side. Therefore, give Hike SEO a try for notable features like competitor analysis and technical SEO improvements.

So what are you waiting for? Try Hike SEO today to climb the ranks in the search results.