How to Reduce Cumulative Layout Shift (CLS) in Webflow for a Smoother User Experience

Cumulative Layout Shift (CLS) is a key metric within Google’s Core Web Vitals that directly impacts the user experience on your website. It measures how much the visible elements of a page unexpectedly move while the page is still loading. A high CLS score can frustrate users as it leads to unexpected shifts in the layout, causing them to misclick or lose their place while reading.

In Webflow, reducing CLS is crucial for providing a smoother, more stable experience for your visitors, and it can also improve your SEO rankings. Below are some effective ways to minimize CLS in your Webflow projects.

1. Set Explicit Image Dimensions

One of the most common causes of CLS is loading images without predefined dimensions. When the browser doesn't know the size of an image in advance, it cannot allocate space for it, which can cause the content around it to shift when the image finally loads.

How to Fix in Webflow:

• Always set explicit width and height attributes for your images.
• Use Webflow’s image settings panel to specify the dimensions for all images.
• Use responsive images, which Webflow generates automatically, to ensure the correct image sizes load across different devices.

2. Predefine Space for Ads, iFrames, and Embeds

Ads, embedded content, and iframes often cause layout shifts as they load. To avoid this, allocate space for these elements in your design even before they load.

How to Fix in Webflow:

• Use a placeholder or container with fixed dimensions for any embedded content.
• Make sure that any ads or external scripts you are using have a defined width and height in Webflow, ensuring the layout remains stable as they load.

3. Use Web Fonts Efficiently

Web fonts can be a major cause of CLS if the fallback font is significantly different in size or appearance. The browser initially loads a fallback font while the web font downloads, leading to a visible "flash" or shift in text once the web font is rendered.

How to Fix in Webflow:

• Use the font-display: swap; CSS property to ensure that text remains visible while web fonts load.
• Minimize the number of web fonts and font weights used across your website to reduce the loading time.
• Consider using system fonts for body text or lower-priority elements to avoid layout shifts altogether.

4. Reserve Space for Dynamic Content

Dynamic content, such as pop-ups, sliders, and notifications, can shift other elements around as they appear or load. Pre-allocating space for these elements can prevent layout shifts.

How to Fix in Webflow:

• Use flexbox or grid layouts to create a structured design that accommodates dynamic content without shifting other elements.
• For sliders or carousels, make sure their dimensions are fixed or responsive so that the content within them doesn’t cause shifts.

5. Optimize Fonts and CSS Delivery

The way fonts and CSS files are loaded can affect how quickly the browser can render a stable layout. If a page's CSS is not prioritized, it can cause layout shifts once the styling is applied.

How to Fix in Webflow:

• Minimize unused CSS and only include styles that are essential for the current page.
• Optimize and preload key CSS files using the built-in features of Webflow to ensure quicker rendering of important layout-related styles.

6. Lazy Load Images and Videos

While lazy loading can improve page load time, improperly implemented lazy loading can contribute to CLS if images and videos pop into the layout without reserved space.

How to Fix in Webflow:

• Use Webflow’s built-in lazy loading feature for images and videos, but ensure that you set explicit height and width attributes to reserve space for them as they load.
• If you use third-party lazy-loading scripts, make sure they are configured to maintain layout stability.

7. Test and Monitor CLS in Webflow

Regular testing is key to keeping CLS under control. Webflow offers several tools to help ensure that your layout remains stable as you make changes to your site.

How to Test:

• Use Webflow’s built-in performance checker or browser developer tools to monitor the CLS score of your site.
• Run Google Lighthouse audits within Chrome DevTools to analyze and optimize your site’s performance.
• Continuously track the CLS score through Google Search Console and tweak elements that contribute to shifts.

Final Thoughts

Reducing Cumulative Layout Shift in Webflow not only provides a smoother user experience but also improves your site's SEO performance. By paying attention to key aspects such as image dimensions, fonts, dynamic content, and layout structure, you can ensure that your site loads in a stable and user-friendly manner.

Remember that minimizing CLS is an ongoing process. As you add new content, features, or elements to your Webflow site, continue to monitor your CLS score and make adjustments to maintain a high-quality user experience.

By incorporating these strategies, you’ll set yourself up for success, delivering a website that is both visually appealing and performance-optimized.

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