When Google first introduced Core Web Vitals, the SEO community focused heavily on loading speeds. However, as we move through 2025, visual stability has become equally critical for maintaining search visibility. While many discussed Cumulative Layout Shift: Google’s next ranking factor for 2023, the reality is that CLS has evolved into a foundational pillar of user experience that directly impacts conversion rates and search engine results pages (SERPs) today.
Cumulative Layout Shift (CLS) measures the sum total of all individual layout shift scores for every unexpected layout shift that occurs during the entire lifespan of a page. A poor score means elements on your page are “jumping” around, causing users to click the wrong buttons or lose their place while reading.
To ensure your site remains competitive, here are 15 ways to optimize CLS for better rankings in 2025.
- Set Explicit Dimensions for Images and Video
The most common cause of layout shifts is browser ignorance regarding an image’s size until it finishes downloading. Always include width and height attributes on your <img> and <video> tags. This allows the browser to reserve the correct amount of space (the aspect ratio) before the asset actually loads.
- Reserve Space for Ad Slots
Ads are notorious for causing dramatic layout shifts. In 2025, the best practice is to pre-allocate the largest possible space for an ad slot using a <div> with a defined height and width. If the ad fails to load, use a placeholder or a “collapse” animation that doesn’t disrupt the user’s reading flow.
- Use Aspect Ratio Boxes in CSS
Modern CSS allows you to use the aspect-ratio property. By defining an aspect ratio for containers (e.g., aspect-ratio: 16 / 9), you ensure that the container maintains its shape even before the content—like a YouTube embed or a hero image—is fully rendered.
- Avoid Inserting Content Above Existing Content
Never dynamically inject content (like newsletter sign-up bars or “related post” links) above content that has already loaded, unless it is in response to a user action. If you must add a top banner, ensure the space is reserved in the initial HTML/CSS to prevent the rest of the page from “dropping” down.
- Optimize Web Font Loading (FOIT/FOUT)
When a browser switches from a fallback font to a custom web font, it can cause text to re-flow, leading to a layout shift. Use font-display: swap; in your CSS to show a fallback font immediately. To minimize the shift, choose a fallback font that closely matches the dimensions of your custom font.
- Preload Key Web Fonts
To further reduce font-related shifts, use <link rel=”preload”> for your primary brand fonts. This instructs the browser to download the font file as a high priority, increasing the likelihood that it will be ready by the time the text is rendered.
- Manage Dynamic Content with “Placeholders”
If your site relies on dynamic content (like live price tickers or weather updates), use “skeleton screens” or gray-box placeholders. This signals to the browser and the user that content is coming, maintaining the visual structure while the data is fetched.
- Use Transform Animations Instead of Box Model Changes
When animating elements, avoid properties like top, bottom, left, right, width, or height. These trigger “layout” changes. Instead, use CSS transform: translate() or scale(), which are handled by the compositor and do not cause layout shifts that contribute to your CLS score.
- Optimize Late-Loading CSS
If your CSS is split into multiple files, a late-loading file can suddenly change the layout of elements already on the screen. Ensure that “critical CSS” (the styles needed for the top half of the page) is inlined or loaded with the highest priority.
- Handle “Back/Forward Cache” Correctly
In 2025, browsers use a Back/Forward Cache (bfcache) to make navigation instantaneous. If your JavaScript modifies the DOM in a way that isn’t preserved when the user hits the “back” button, it can cause a shift upon return. Ensure your scripts are bfcache-compatible to maintain stability.
- Limit the Use of Embeds (iFrames)
Embeds from social media (Twitter threads, Instagram posts) often load their own styles and dimensions after the main page is ready. If you use embeds, wrap them in a container with a fixed minimum height to “box in” the content and prevent it from expanding the page late.
- Use the “Layout Instability API” for Testing
To truly optimize, you need data. Use the Layout Instability API through Google Search Console or PageSpeed Insights to identify exactly which elements are moving. In 2025, these tools provide specific “rect” coordinates of the shifting elements.
- Audit Third-Party Scripts
Third-party widgets (chatbots, review stars, cookie banners) are frequent CLS offenders. Regularly audit your third-party scripts. If a widget causes a significant shift, consider lazy-loading it or placing it in a fixed-position container that doesn’t push other elements.
- Be Cautious with Infinite Scroll
Infinite scrolling can lead to layout shifts if the footer or “loading” indicators jump around as new items are added. Ensure your “loading” container has a set height and that new content is appended smoothly without resizing the scrollbar abruptly.
- Standardize Button and Icon Sizes
Ensure that all buttons and icons have consistent padding and line heights. Often, an icon font loading a millisecond late will cause a button to expand slightly, pushing a line of text down. Hard-coding these dimensions in your CSS prevents this “micro-shift.”
Conclusion: Visual Stability as a Competitive Edge
While the industry buzz began with Cumulative Layout Shift: Google’s next ranking factor for 2023, the focus in 2025 has shifted toward the “User Experience” (UX) holistically. A stable website builds trust; a shifting website leads to frustration and high bounce rates.
By implementing these 15 optimization strategies, you aren’t just pleasing an algorithm—you are providing a professional, polished experience for your visitors. In 2025, visual stability is a prerequisite for success. Start by auditing your top-performing pages today and ensuring that every element has its place and stays there. For more technical guidance, refer to the official web.dev documentation on CLS.