{"id":3960,"date":"2025-11-06T14:39:06","date_gmt":"2025-11-06T12:39:06","guid":{"rendered":"https:\/\/fastpixel.io\/?p=3960"},"modified":"2025-11-06T14:39:54","modified_gmt":"2025-11-06T12:39:54","slug":"understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors","status":"publish","type":"post","link":"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/","title":{"rendered":"Understanding CLS (Cumulative Layout Shift): Why Stable Layouts Matter for Your Visitors"},"content":{"rendered":"<p>Ever been reading a website when suddenly everything jumps and you lose your place? Or worse, you&#8217;re about to tap a button and BAM, the page shifts and you click an ad instead? That&#8217;s exactly what Cumulative Layout Shift (CLS) measures.<\/p>\n\n\n\n<p>Think of CLS as a stability score for your website. It tracks how much your page content bounces around unexpectedly while loading. Lower scores mean a rock-solid experience; higher scores mean your visitors are dealing with a jumpy, frustrating page.<\/p>\n\n\n\n<p>This matters more than you might think. Nobody enjoys wrestling with a page that won&#8217;t stay still. Beyond frustrating your visitors, poor CLS can hurt your search rankings since Google counts it as a Core Web Vital. <\/p>\n\n\n\n<p>Get this right, and you&#8217;re improving both user satisfaction and SEO in one go.<\/p>\n\n\n\n<div class=\"wp-block-group has-border-color has-palette-color-8-background-color has-background is-layout-constrained wp-container-core-group-is-layout-239228e0 wp-block-group-is-layout-constrained\" style=\"border-color:#888888;border-width:1px;border-radius:20px;padding-top:var(--wp--preset--spacing--60);padding-right:var(--wp--preset--spacing--60);padding-bottom:var(--wp--preset--spacing--60);padding-left:var(--wp--preset--spacing--60)\">\n<div class=\"wp-block-group is-nowrap is-layout-flex wp-container-core-group-is-layout-6c531013 wp-block-group-is-layout-flex\">\n<div class=\"wp-block-outermost-icon-block\"><div class=\"icon-container\" style=\"width:25px;transform:rotate(0deg) scaleX(1) scaleY(1)\"><svg viewbox=\"0 0 24 24\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" aria-hidden=\"true\"><path fill-rule=\"evenodd\" clip-rule=\"evenodd\" d=\"M11.934 7.406a1 1 0 0 0 .914.594H19a.5.5 0 0 1 .5.5v9a.5.5 0 0 1-.5.5H5a.5.5 0 0 1-.5-.5V6a.5.5 0 0 1 .5-.5h5.764a.5.5 0 0 1 .447.276l.723 1.63Zm1.064-1.216a.5.5 0 0 0 .462.31H19a2 2 0 0 1 2 2v9a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V6a2 2 0 0 1 2-2h5.764a2 2 0 0 1 1.789 1.106l.445 1.084ZM8.5 10.5h7V12h-7v-1.5Zm7 3.5h-7v1.5h7V14Z\"><\/path><\/svg><\/div><\/div>\n\n\n\n<p class=\"has-medium-font-size\"><strong>More on this topic<\/strong><\/p>\n<\/div>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/fastpixel.io\/fr\/blog\/guide-to-core-web-vitals\/\" data-type=\"link\" data-id=\"https:\/\/fastpixel.io\/blog\/guide-to-core-web-vitals\/\">Guide to Core Web Vitals: What Every Website Owner Needs to Know<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/fastpixel.io\/fr\/blog\/largest-contentful-paint-explained\/\">What Is LCP and How to Improve It: A Non-Technical Guide<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/fastpixel.io\/fr\/blog\/interaction-to-next-paint-inp-explained\/\">INP for Beginners: How to Make Every Click Feel Instant<\/a><\/li>\n<\/ul>\n<\/div>\n\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_81 counter-hierarchy ez-toc-counter ez-toc-custom ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #000000;color:#000000\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #000000;color:#000000\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewbox=\"0 0 24 24\" version=\"1.2\" baseprofile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#why-visual-stability-matters-to-your-websites-success\" >Why visual stability matters to your website&#8217;s success<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#how-to-measure-cls\" >How to measure CLS<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#want-more-detailed-analysis\" >Want more detailed analysis?<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#what-causes-a-poor-cls-score\" >What causes a poor CLS score?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#how-to-improve-cls\" >How to improve CLS<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#always-include-image-dimensions\" >Always include image dimensions<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#reserve-space-for-ads-and-dynamic-content\" >Reserve space for ads and dynamic content<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#optimize-web-font-loading\" >Optimize web font loading<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#avoid-animating-layout-changing-properties\" >Avoid animating layout-changing properties<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#optimize-third-party-scripts\" >Optimize third-party scripts<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#enable-backforward-cache\" >Enable back\/forward cache<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#use-an-optimization-plugin-for-wordpress\" >Use an optimization plugin for WordPress<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#how-to-know-youve-improved-cls\" >How to know you&#8217;ve improved CLS<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#test-again-with-pagespeed-insights\" >Test again with PageSpeed Insights<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#use-the-performance-tab-in-chrome-devtools\" >Use the Performance tab in Chrome DevTools<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#monitor-user-engagement\" >Monitor user engagement<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#common-pitfalls-and-things-to-watch\" >Common pitfalls and things to watch<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#try-fastpixel-and-see-how-much-faster-your-site-loads\" >Try FastPixel and see how much faster your site loads<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-19\" href=\"https:\/\/fastpixel.io\/fr\/blog\/understanding-cls-cumulative-layout-shift-why-stable-layouts-matter-for-your-visitors\/#faqs\" >FAQs<\/a><\/li><\/ul><\/nav><\/div>\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"why-visual-stability-matters-to-your-websites-success\"><\/span>Why visual stability matters to your website&#8217;s success<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Someone lands on your blog to read an article. They see the headline, start reading the first paragraph, and then whoosh, an image loads and pushes everything down. They&#8217;ve lost their spot, and now they&#8217;re annoyed.<\/p>\n\n\n\n<figure class=\"wp-block-video\"><video height=\"1020\" style=\"aspect-ratio: 1316 \/ 1020;\" width=\"1316\" autoplay controls loop muted src=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/layout-instability.webm\"><\/video><figcaption class=\"wp-element-caption\">Layout instability. Credits for the video to <a href=\"https:\/\/web.dev\/articles\/cls\" data-type=\"link\" data-id=\"https:\/\/web.dev\/articles\/cls\" target=\"_blank\" rel=\"noreferrer noopener\">web.dev<\/a><\/figcaption><\/figure>\n\n\n\n<p>Or imagine someone shopping on your site. They&#8217;re ready to buy, finger hovering over &#8220;Add to Cart,&#8221; when suddenly a banner appears at the top and shifts that button down. They accidentally tap &#8220;Subscribe to Newsletter&#8221; instead. Frustrating, right?<\/p>\n\n\n\n<p>These aren&#8217;t just minor annoyances. Layout shifts have real consequences:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>People leave<\/strong>: When pages feel broken or chaotic, visitors bounce. They assume something&#8217;s wrong and go elsewhere.<\/li>\n\n\n\n<li><strong>Mistakes happen<\/strong>: Unexpected shifts lead to misclicks. Users hit the wrong buttons, close tabs they meant to keep open, or trigger actions they didn&#8217;t intend.<\/li>\n\n\n\n<li><strong>Trust erodes<\/strong>: An unstable website feels unprofessional. First impressions matter, and a jumpy page doesn&#8217;t inspire confidence.<\/li>\n\n\n\n<li><strong>Rankings drop<\/strong>: Google explicitly uses CLS in its ranking algorithm. While 72 percent of desktop sites and 79 percent of mobile sites achieved good CLS scores by 2024, those with poor scores face competitive disadvantages.<\/li>\n<\/ul>\n\n\n\n<p>Whether you&#8217;re blogging, selling products, showcasing your portfolio, or running any kind of site, CLS directly impacts how people perceive and interact with your content.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"how-to-measure-cls\"><\/span>How to measure CLS<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>You don&#8217;t need any special skills or expensive tools to check your CLS score. The easiest method is using PageSpeed Insights \u2013 Google&#8217;s free tool that shows exactly how your page performs for real visitors.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Go to <a href=\"https:\/\/pagespeed.web.dev\/\">PageSpeed Insights<\/a>.<\/li>\n\n\n\n<li>Enter your website URL and click Analyze.<\/li>\n\n\n\n<li>Wait while it gathers both &#8220;field data&#8221; (from real Chrome users who visited your site) and &#8220;lab data&#8221; (a simulated test).<\/li>\n<\/ul>\n\n\n\n<p>Once finished, you&#8217;ll see a section labeled Cumulative Layout Shift (CLS) under Core Web Vitals assessment.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"1291\" height=\"634\" src=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/10\/cls-core-web-vitals.png\" alt=\"\" class=\"wp-image-3908\" srcset=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/10\/cls-core-web-vitals.png 1291w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/10\/cls-core-web-vitals-300x147.png 300w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/10\/cls-core-web-vitals-1024x503.png 1024w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/10\/cls-core-web-vitals-768x377.png 768w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/10\/cls-core-web-vitals-18x9.png 18w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/10\/cls-core-web-vitals-360x177.png 360w\" sizes=\"(max-width: 1291px) 100vw, 1291px\" \/><\/figure>\n\n\n\n<p>This tells you how visually stable your page is \u2013 basically, how much stuff is jumping around while people try to use it.<\/p>\n\n\n\n<p>After that, scroll down and click the CLS link to see audits specifically related to layout shifts.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"1062\" height=\"500\" src=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cls-insights.png\" alt=\"\" class=\"wp-image-4005\" srcset=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cls-insights.png 1062w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cls-insights-300x141.png 300w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cls-insights-1024x482.png 1024w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cls-insights-768x362.png 768w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cls-insights-18x8.png 18w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cls-insights-360x169.png 360w\" sizes=\"(max-width: 1062px) 100vw, 1062px\" \/><\/figure>\n\n\n\n<p>You can click through the listed insights and diagnostics to see what&#8217;s causing your shifts. That&#8217;s where your optimization work begins.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"want-more-detailed-analysis\"><\/span>Want more detailed analysis?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>PageSpeed Insights works great for most people, but if you want to dig deeper:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Chrome DevTools<\/strong>: Open your site, press F12, navigate to the Lighthouse tab, and run an audit. You&#8217;ll see your CLS score plus visual indicators showing exactly which elements are shifting.<\/li>\n\n\n\n<li><strong>WebPageTest<\/strong>: Head to <a href=\"https:\/\/www.webpagetest.org\" target=\"_blank\" rel=\"noreferrer noopener\">WebPageTest.org<\/a> for detailed testing. You can simulate different devices, connection speeds, and geographic locations. The filmstrip view shows frame-by-frame exactly when shifts occur.<\/li>\n<\/ul>\n\n\n\n<p>For beginners, though, PageSpeed Insights provides everything you need \u2013 clear scores, plain-English explanations, and actionable suggestions.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"what-causes-a-poor-cls-score\"><\/span>What causes a poor CLS score?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>When CLS scores climb, certain patterns emerge. Here are the usual suspects:<\/p>\n\n\n\n<p>\u274c <strong>Images missing dimensions<\/strong><\/p>\n\n\n\n<p>This is the big one. Images cause roughly 60% of layout shift problems. <\/p>\n\n\n\n<p>When you add an image without specifying its size, the browser initially allocates zero space. Then the image downloads, and suddenly everything below it gets shoved down to make room.<\/p>\n\n\n\n<p>\u274c <strong>Ads and embedded content<\/strong><\/p>\n\n\n\n<p>Advertisement slots, YouTube videos, Twitter feeds, Instagram posts \u2013 these all load after your page renders. Without pre-allocated space, they insert themselves and push existing content out of the way.<\/p>\n\n\n\n<p>\u274c <strong>Web fonts loading late<\/strong><\/p>\n\n\n\n<p>You pick a beautiful custom font for your site. It looks great, but here&#8217;s what happens: the browser initially shows text in a fallback font, then swaps to your custom font once it loads. If the fonts have different sizes, boom \u2013 layout shift.<\/p>\n\n\n\n<p>\u274c <strong>Content popping in<\/strong><\/p>\n\n\n\n<p>Banners, notifications, cookie consent forms, promotional bars \u2013 any content that JavaScript adds after initial load can cause shifts if not handled properly.<\/p>\n\n\n\n<p>\u274c <strong>Bad animations<\/strong><\/p>\n\n\n\n<p>Some CSS animations trigger the browser to recalculate the positions of multiple elements. These &#8220;layout-affecting&#8221; animations cause shifts across your entire page.<\/p>\n\n\n\n<p>\u274c <strong>Third-party widgets<\/strong><\/p>\n\n\n\n<p>Chat boxes, social sharing buttons, comment sections, analytics \u2013 these external scripts can inject content or modify your layout unpredictably.<\/p>\n\n\n\n<p>Identifying which issues affect your specific site is step one. PageSpeed Insights highlights the main culprits in its diagnostic report.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"how-to-improve-cls\"><\/span>How to improve CLS<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Ready to make your website more stable? Here&#8217;s how you can tackle CLS issues without needing to be a developer.<\/p>\n\n\n\n<p>The icon next to a heading means FastPixel can help improve that specific area!<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"always-include-image-dimensions\"><\/span><img decoding=\"async\" class=\"wp-image-3876\" style=\"width: 30px;\" src=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/10\/FastPixel_Icon_Smile.svg\" alt=\"\">Always include image dimensions<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>This is the biggest, most effective fix for most websites. When you add images or videos to your site, always specify their width and height in your HTML or CSS.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Set explicit <code>width<\/code> and <code>height<\/code> attributes on all images: <code>&lt;img src=&quot;hero.jpg&quot; width=&quot;1200&quot; height=&quot;600&quot; alt=&quot;Hero image&quot;&gt;<\/code><\/li>\n\n\n\n<li>Use CSS <code>aspect-ratio<\/code> to maintain proportions across different screen sizes.<\/li>\n\n\n\n<li>For responsive images, use <code>max-width: 100%<\/code> and <code>height: auto<\/code> in CSS while keeping the HTML dimensions set.<\/li>\n\n\n\n<li>Make sure your CMS or page builder adds these attributes automatically.<\/li>\n<\/ul>\n\n\n\n<p>When the browser knows an image&#8217;s dimensions before it loads, it can reserve the right amount of space, preventing shifts.<\/p>\n\n\n\n<p>You can use a WordPress plugin like <a href=\"https:\/\/fastpixel.io\/fr\/\" data-type=\"link\" data-id=\"https:\/\/fastpixel.io\/\">FastPixel<\/a> to add missing image dimensions with a simple setting.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"1814\" height=\"883\" src=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/fastpixel-add-missing-image-dimensions.png\" alt=\"\" class=\"wp-image-4011\" srcset=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/fastpixel-add-missing-image-dimensions.png 1814w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/fastpixel-add-missing-image-dimensions-300x146.png 300w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/fastpixel-add-missing-image-dimensions-1024x498.png 1024w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/fastpixel-add-missing-image-dimensions-768x374.png 768w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/fastpixel-add-missing-image-dimensions-1536x748.png 1536w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/fastpixel-add-missing-image-dimensions-18x9.png 18w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/fastpixel-add-missing-image-dimensions-360x175.png 360w\" sizes=\"(max-width: 1814px) 100vw, 1814px\" \/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"reserve-space-for-ads-and-dynamic-content\"><\/span>Reserve space for ads and dynamic content<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>If you have advertisements, social media embeds, or other dynamic content, don&#8217;t let them surprise your visitors by appearing out of nowhere.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Create placeholder containers with minimum heights that match your typical ad or embed sizes.<\/li>\n\n\n\n<li>Use CSS <code>min-height<\/code> properties to hold space even if the content fails to load.<\/li>\n\n\n\n<li>For social media embeds (Twitter, Instagram, YouTube), consider using facade techniques \u2013 show a lightweight placeholder image that users click to load the full embed.<\/li>\n\n\n\n<li>Avoid inserting ads or banners at the top of your content that push everything down.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"optimize-web-font-loading\"><\/span><img decoding=\"async\" class=\"wp-image-3876\" style=\"width: 30px;\" src=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/10\/FastPixel_Icon_Smile.svg\" alt=\"\">Optimize web font loading<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Custom fonts are a common source of CLS when text suddenly changes size or style after the page loads.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Preload critical fonts<\/strong>: Add <code>&lt;link rel=\"preload\" href=\"font.woff2\" as=\"font\" type=\"font\/woff2\" crossorigin&gt;<\/code> in your <code>&lt;head&gt;<\/code> section.<\/li>\n\n\n\n<li><strong>Use font-display properly<\/strong>: Set <code>font-display: optional<\/code> in your CSS \u2013 this gives fonts a very short time to load, and if they don&#8217;t make it, the browser sticks with the system font (which then caches for next time).<\/li>\n\n\n\n<li><strong>Match fallback fonts<\/strong>: Use CSS properties like <code>size-adjust<\/code>, <code>ascent-override<\/code>, and <code>descent-override<\/code> to make your fallback font match your custom font&#8217;s dimensions as closely as possible.<\/li>\n\n\n\n<li><strong>Consider system fonts<\/strong>: If possible, use system fonts like <code>-apple-system<\/code>, <code>BlinkMacSystemFont<\/code>, or <code>Segoe UI<\/code> \u2013 they load instantly because they&#8217;re already on the user&#8217;s device.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"avoid-animating-layout-changing-properties\"><\/span>Avoid animating layout-changing properties<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Some CSS animations trigger layout recalculations, which can cause shifts and hurt performance.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Don&#8217;t animate properties like <code>top<\/code>, <code>left<\/code>, <code>width<\/code>, <code>height<\/code>, <code>margin<\/code>, or <code>padding<\/code>.<\/li>\n\n\n\n<li>Instead, use <code>transform<\/code> and <code>opacity<\/code> animations, which don&#8217;t trigger layout shifts.<\/li>\n\n\n\n<li>Use CSS transitions like <code>transform: translateY()<\/code> for smooth movement without causing CLS issues.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"optimize-third-party-scripts\"><\/span><img decoding=\"async\" class=\"wp-image-3876\" style=\"width: 30px;\" src=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/10\/FastPixel_Icon_Smile.svg\" alt=\"\">Optimize third-party scripts<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>External scripts can inject content or modify your page in ways that cause unexpected shifts.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Load third-party scripts asynchronously using <code>async<\/code> or <code>defer<\/code> attributes.<\/li>\n\n\n\n<li>Place scripts at the bottom of your HTML when possible.<\/li>\n\n\n\n<li>Use a tag manager to control when and how scripts load.<\/li>\n\n\n\n<li>Regularly audit which third-party scripts you actually need \u2013 remove unused ones.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"enable-backforward-cache\"><\/span>Enable back\/forward cache<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>The back\/forward cache (bfcache) stores pages in memory so they load instantly when users hit the back button, with no layout shifts at all.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Avoid using <code>unload<\/code> event listeners, which prevent bfcache.<\/li>\n\n\n\n<li>Make sure your pages don&#8217;t have blocking scripts or resource-intensive operations.<\/li>\n\n\n\n<li>Test your pages to confirm they&#8217;re eligible for bfcache.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"use-an-optimization-plugin-for-wordpress\"><\/span>Use an optimization plugin for WordPress<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>If you&#8217;re running WordPress, tools like <a href=\"https:\/\/fastpixel.io\/fr\/\">FastPixel<\/a> can automatically handle many CLS optimizations for you \u2013 image dimension fixes, critical CSS generation, font optimization, and script management.<\/p>\n\n\n\n<p>Picking the right preset and letting the plugin handle the technical details is often the fastest path to better CLS scores, especially if you&#8217;re not comfortable diving into code.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"how-to-know-youve-improved-cls\"><\/span>How to know you&#8217;ve improved CLS<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>You&#8217;ve made changes \u2013 now confirm they helped.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"test-again-with-pagespeed-insights\"><\/span>Test again with PageSpeed Insights<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Run another test on your optimized page. Look at the CLS score and compare it to your baseline.<\/p>\n\n\n\n<p>A drop from 0.28 to 0.07? That&#8217;s a major win. Your visitors will definitely notice the difference.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"use-the-performance-tab-in-chrome-devtools\"><\/span>Use the Performance tab in Chrome DevTools<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>For advanced users, open DevTools, go to Performance, click Record, then reload your page.<\/p>\n\n\n\n<p>Under Insights, click Layout shift culprits to investigate the cause of layout shifts.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"1932\" height=\"944\" src=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/layout-shift-culprits-devtools.png\" alt=\"\" class=\"wp-image-4015\" srcset=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/layout-shift-culprits-devtools.png 1932w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/layout-shift-culprits-devtools-300x147.png 300w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/layout-shift-culprits-devtools-1024x500.png 1024w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/layout-shift-culprits-devtools-768x375.png 768w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/layout-shift-culprits-devtools-1536x751.png 1536w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/layout-shift-culprits-devtools-18x9.png 18w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/layout-shift-culprits-devtools-360x176.png 360w\" sizes=\"(max-width: 1932px) 100vw, 1932px\" \/><\/figure>\n\n\n\n<p>Ideally, you&#8217;ll have this audit passed after your optimizations.<\/p>\n\n\n\n<p>This visual debugging helps you pinpoint any remaining problem areas.<\/p>\n\n\n\n<p>You can also use the built-in AI assistant to quickly identify what\u2019s triggering those layout shifts.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"1888\" height=\"1058\" src=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/ai-assistance-dev-tools.png\" alt=\"\" class=\"wp-image-4017\" srcset=\"https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/ai-assistance-dev-tools.png 1888w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/ai-assistance-dev-tools-300x168.png 300w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/ai-assistance-dev-tools-1024x574.png 1024w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/ai-assistance-dev-tools-768x430.png 768w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/ai-assistance-dev-tools-1536x861.png 1536w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/ai-assistance-dev-tools-18x10.png 18w, https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/ai-assistance-dev-tools-360x202.png 360w\" sizes=\"(max-width: 1888px) 100vw, 1888px\" \/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"monitor-user-engagement\"><\/span>Monitor user engagement<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Numbers tell part of the story; behavior tells the rest.<\/p>\n\n\n\n<p>After fixing CLS issues, watch for:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Lower bounce rates (people stick around longer)<\/li>\n\n\n\n<li>Higher time on page (they&#8217;re actually reading, not struggling)<\/li>\n\n\n\n<li>Better conversion rates (they can complete actions without misclicks)<\/li>\n\n\n\n<li>Fewer customer support complaints about website usability<\/li>\n<\/ul>\n\n\n\n<p>These behavioral improvements confirm your technical optimizations are creating real-world benefits.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"common-pitfalls-and-things-to-watch\"><\/span>Common pitfalls and things to watch<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>A few common traps catch people working on CLS:<\/p>\n\n\n\n<p><strong>Mobile usually struggles more<\/strong>: Smartphones have smaller screens, slower processors, and less reliable connections. Always test mobile performance separately. Your desktop might score perfectly, while your mobile suffers.<\/p>\n\n\n\n<p><strong>The whole page matters<\/strong>: CLS tracks shifts throughout the page, not just what&#8217;s visible initially. Content further down still counts as users scroll. Make sure your entire page maintains stability.<\/p>\n\n\n\n<p><strong>User actions don&#8217;t count against you<\/strong>: If someone clicks a button and content moves within half a second, that&#8217;s fine. It&#8217;s an expected response to their action. CLS only penalizes unexpected shifts.<\/p>\n\n\n\n<p><strong>Cookie banners need careful implementation<\/strong>: Those &#8220;Accept Cookies&#8221; bars at the top or bottom? If they insert into the page and push content around, they hurt CLS. Instead, make them overlay existing content using fixed positioning.<\/p>\n\n\n\n<p><strong>Infinite scroll requires planning<\/strong>: Loading more content as users scroll is great for engagement, but poor implementation causes ongoing shifts. Reserve space for loading indicators and new content before it appears.<\/p>\n\n\n\n<p><strong>Background images count too<\/strong>: Large background images loaded via CSS can cause shifts just like regular images. Optimize them the same way. Preload critical backgrounds and set dimensions.<\/p>\n\n\n\n<div class=\"wp-block-group has-border-color has-palette-color-4-border-color has-palette-color-6-background-color has-background is-vertical is-content-justification-left is-layout-flex wp-container-core-group-is-layout-e21fc307 wp-block-group-is-layout-flex\" style=\"border-width:1px;border-radius:20px;margin-top:var(--wp--preset--spacing--60);margin-bottom:var(--wp--preset--spacing--60);padding-top:var(--wp--preset--spacing--60);padding-right:var(--wp--preset--spacing--60);padding-bottom:var(--wp--preset--spacing--60);padding-left:var(--wp--preset--spacing--60)\">\n<h3 class=\"wp-block-heading\" style=\"margin-top:0;margin-right:0;margin-bottom:0;margin-left:0;padding-top:0;padding-right:0;padding-bottom:0;padding-left:0\"><span class=\"ez-toc-section\" id=\"try-fastpixel-and-see-how-much-faster-your-site-loads\"><\/span>Try FastPixel and see how much faster your site loads<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Improve loading times, enhance user experience, and give your website the performance edge it needs.<\/p>\n\n\n\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\" href=\"https:\/\/wordpress.org\/plugins\/fastpixel-website-accelerator\/\" target=\"_blank\" rel=\"noreferrer noopener\">Commencer<\/a><\/div>\n<\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"faqs\"><\/span>FAQs<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n<div class=\"wp-block-uagb-faq uagb-faq__outer-wrap uagb-block-cad6f48e uagb-faq-icon-row uagb-faq-layout-accordion uagb-faq-expand-first-true uagb-faq-inactive-other-true uagb-faq__wrap uagb-buttons-layout-wrap uagb-faq-equal-height\" data-faqtoggle=\"true\" role=\"tablist\"><div class=\"wp-block-uagb-faq-child uagb-faq-child__outer-wrap uagb-faq-item uagb-block-53998276\" role=\"tab\" tabindex=\"0\"><div class=\"uagb-faq-questions-button uagb-faq-questions\">\t\t\t<span class=\"uagb-icon uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M432 256c0 17.69-14.33 32.01-32 32.01H256v144c0 17.69-14.33 31.99-32 31.99s-32-14.3-32-31.99v-144H48c-17.67 0-32-14.32-32-32.01s14.33-31.99 32-31.99H192v-144c0-17.69 14.33-32.01 32-32.01s32 14.32 32 32.01v144h144C417.7 224 432 238.3 432 256z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<span class=\"uagb-icon-active uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M400 288h-352c-17.69 0-32-14.32-32-32.01s14.31-31.99 32-31.99h352c17.69 0 32 14.3 32 31.99S417.7 288 400 288z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t<span class=\"uagb-question\"><strong>What is CLS?<\/strong><\/span><\/div><div class=\"uagb-faq-content\"><p>CLS measures how much the visible content of a webpage unexpectedly moves around while it\u2019s loading \u2014 for example, when text shifts down because an image appears above it. <a href=\"https:\/\/web.dev\/articles\/cls?utm_source=chatgpt.com\" target=\"_blank\" rel=\"noreferrer noopener\"><\/a><\/p><\/div><\/div><div class=\"wp-block-uagb-faq-child uagb-faq-child__outer-wrap uagb-faq-item uagb-block-b7ff5103\" role=\"tab\" tabindex=\"0\"><div class=\"uagb-faq-questions-button uagb-faq-questions\">\t\t\t<span class=\"uagb-icon uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M432 256c0 17.69-14.33 32.01-32 32.01H256v144c0 17.69-14.33 31.99-32 31.99s-32-14.3-32-31.99v-144H48c-17.67 0-32-14.32-32-32.01s14.33-31.99 32-31.99H192v-144c0-17.69 14.33-32.01 32-32.01s32 14.32 32 32.01v144h144C417.7 224 432 238.3 432 256z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<span class=\"uagb-icon-active uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M400 288h-352c-17.69 0-32-14.32-32-32.01s14.31-31.99 32-31.99h352c17.69 0 32 14.3 32 31.99S417.7 288 400 288z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t<span class=\"uagb-question\"><strong>Why should I care about my CLS score?<\/strong><\/span><\/div><div class=\"uagb-faq-content\"><p>Because if things on your site jump around, visitors can mis-click, get frustrated, leave early or feel the site is sloppy. A low (good) CLS means your page feels stable and trustworthy. <a href=\"https:\/\/www.corewebvitals.io\/core-web-vitals\/cumulative-layout-shift?utm_source=chatgpt.com\" target=\"_blank\" rel=\"noreferrer noopener\"><\/a><\/p><\/div><\/div><div class=\"wp-block-uagb-faq-child uagb-faq-child__outer-wrap uagb-faq-item uagb-block-22b59def\" role=\"tab\" tabindex=\"0\"><div class=\"uagb-faq-questions-button uagb-faq-questions\">\t\t\t<span class=\"uagb-icon uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M432 256c0 17.69-14.33 32.01-32 32.01H256v144c0 17.69-14.33 31.99-32 31.99s-32-14.3-32-31.99v-144H48c-17.67 0-32-14.32-32-32.01s14.33-31.99 32-31.99H192v-144c0-17.69 14.33-32.01 32-32.01s32 14.32 32 32.01v144h144C417.7 224 432 238.3 432 256z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<span class=\"uagb-icon-active uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M400 288h-352c-17.69 0-32-14.32-32-32.01s14.31-31.99 32-31.99h352c17.69 0 32 14.3 32 31.99S417.7 288 400 288z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t<span class=\"uagb-question\"><strong>What\u2019s a good CLS score to aim for?<\/strong><\/span><\/div><div class=\"uagb-faq-content\"><p>A \u201cgood\u201d CLS score is <strong>0.1 or less<\/strong>. Scores between about 0.1 and 0.25 \u201cneed improvement\u201d, and anything above 0.25 is considered poor. <a href=\"https:\/\/web.dev\/articles\/optimize-cls?utm_source=chatgpt.com\" target=\"_blank\" rel=\"noreferrer noopener\"><\/a><\/p><\/div><\/div><div class=\"wp-block-uagb-faq-child uagb-faq-child__outer-wrap uagb-faq-item uagb-block-25ec6167\" role=\"tab\" tabindex=\"0\"><div class=\"uagb-faq-questions-button uagb-faq-questions\">\t\t\t<span class=\"uagb-icon uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M432 256c0 17.69-14.33 32.01-32 32.01H256v144c0 17.69-14.33 31.99-32 31.99s-32-14.3-32-31.99v-144H48c-17.67 0-32-14.32-32-32.01s14.33-31.99 32-31.99H192v-144c0-17.69 14.33-32.01 32-32.01s32 14.32 32 32.01v144h144C417.7 224 432 238.3 432 256z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<span class=\"uagb-icon-active uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M400 288h-352c-17.69 0-32-14.32-32-32.01s14.31-31.99 32-31.99h352c17.69 0 32 14.3 32 31.99S417.7 288 400 288z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t<span class=\"uagb-question\"><strong>What kinds of things cause a high (bad) CLS?<\/strong><\/span><\/div><div class=\"uagb-faq-content\"><p>Common causes include: images\/videos\/iframes without defined size attributes so they load and push text down; ads or embeds that appear late and shift content; fonts that load and change size after fallback; dynamic content inserted above existing content. <a href=\"https:\/\/web.dev\/articles\/optimize-cls?utm_source=chatgpt.com\" target=\"_blank\" rel=\"noreferrer noopener\"><\/a><\/p><\/div><\/div><div class=\"wp-block-uagb-faq-child uagb-faq-child__outer-wrap uagb-faq-item uagb-block-d51d178d\" role=\"tab\" tabindex=\"0\"><div class=\"uagb-faq-questions-button uagb-faq-questions\">\t\t\t<span class=\"uagb-icon uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M432 256c0 17.69-14.33 32.01-32 32.01H256v144c0 17.69-14.33 31.99-32 31.99s-32-14.3-32-31.99v-144H48c-17.67 0-32-14.32-32-32.01s14.33-31.99 32-31.99H192v-144c0-17.69 14.33-32.01 32-32.01s32 14.32 32 32.01v144h144C417.7 224 432 238.3 432 256z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<span class=\"uagb-icon-active uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M400 288h-352c-17.69 0-32-14.32-32-32.01s14.31-31.99 32-31.99h352c17.69 0 32 14.3 32 31.99S417.7 288 400 288z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t<span class=\"uagb-question\"><strong>How can I check my site\u2019s CLS score?<\/strong><\/span><\/div><div class=\"uagb-faq-content\"><p>You can check via tools like Google PageSpeed Insights, the Chrome Lighthouse audit, or the \u201cCore Web Vitals\u201d report in Google Search Console, which show field and lab data. <\/p><\/div><\/div><div class=\"wp-block-uagb-faq-child uagb-faq-child__outer-wrap uagb-faq-item uagb-block-a3df77be\" role=\"tab\" tabindex=\"0\"><div class=\"uagb-faq-questions-button uagb-faq-questions\">\t\t\t<span class=\"uagb-icon uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M432 256c0 17.69-14.33 32.01-32 32.01H256v144c0 17.69-14.33 31.99-32 31.99s-32-14.3-32-31.99v-144H48c-17.67 0-32-14.32-32-32.01s14.33-31.99 32-31.99H192v-144c0-17.69 14.33-32.01 32-32.01s32 14.32 32 32.01v144h144C417.7 224 432 238.3 432 256z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<span class=\"uagb-icon-active uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M400 288h-352c-17.69 0-32-14.32-32-32.01s14.31-31.99 32-31.99h352c17.69 0 32 14.3 32 31.99S417.7 288 400 288z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t<span class=\"uagb-question\"><strong>If my site loads quickly, does that guarantee a good CLS?<\/strong><\/span><\/div><div class=\"uagb-faq-content\"><p>No. A fast-loading site can still have high CLS if the layout shifts while loading. Speed (loading) and stability (not shifting) are related but separate.<\/p><\/div><\/div><div class=\"wp-block-uagb-faq-child uagb-faq-child__outer-wrap uagb-faq-item uagb-block-5b587ba8\" role=\"tab\" tabindex=\"0\"><div class=\"uagb-faq-questions-button uagb-faq-questions\">\t\t\t<span class=\"uagb-icon uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M432 256c0 17.69-14.33 32.01-32 32.01H256v144c0 17.69-14.33 31.99-32 31.99s-32-14.3-32-31.99v-144H48c-17.67 0-32-14.32-32-32.01s14.33-31.99 32-31.99H192v-144c0-17.69 14.33-32.01 32-32.01s32 14.32 32 32.01v144h144C417.7 224 432 238.3 432 256z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<span class=\"uagb-icon-active uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M400 288h-352c-17.69 0-32-14.32-32-32.01s14.31-31.99 32-31.99h352c17.69 0 32 14.3 32 31.99S417.7 288 400 288z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t<span class=\"uagb-question\"><strong>Can layout shifts caused by user actions affect my CLS?<\/strong><\/span><\/div><div class=\"uagb-faq-content\"><p>Usually no. If a layout change happens right after a user interacts (clicks or taps) and it\u2019s expected (like opening a menu), it doesn\u2019t count toward the CLS score. Only \u201cunexpected\u201d shifts (without user input) are penalised. <\/p><\/div><\/div><div class=\"wp-block-uagb-faq-child uagb-faq-child__outer-wrap uagb-faq-item uagb-block-392e5062\" role=\"tab\" tabindex=\"0\"><div class=\"uagb-faq-questions-button uagb-faq-questions\">\t\t\t<span class=\"uagb-icon uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M432 256c0 17.69-14.33 32.01-32 32.01H256v144c0 17.69-14.33 31.99-32 31.99s-32-14.3-32-31.99v-144H48c-17.67 0-32-14.32-32-32.01s14.33-31.99 32-31.99H192v-144c0-17.69 14.33-32.01 32-32.01s32 14.32 32 32.01v144h144C417.7 224 432 238.3 432 256z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<span class=\"uagb-icon-active uagb-faq-icon-wrap\">\n\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewbox= \"0 0 448 512\"><path d=\"M400 288h-352c-17.69 0-32-14.32-32-32.01s14.31-31.99 32-31.99h352c17.69 0 32 14.3 32 31.99S417.7 288 400 288z\"><\/path><\/svg>\n\t\t\t\t\t\t\t<\/span>\n\t\t\t<span class=\"uagb-question\"><strong>Will improving my CLS help my website\u2019s ranking on Google?<\/strong><\/span><\/div><div class=\"uagb-faq-content\"><p>Yes, CLS is part of the metrics (the \u201cCore Web Vitals\u201d) that Google uses to gauge user experience. A better CLS can improve the overall page experience signal, which may help in search visibility. <\/p><\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>Ever been reading a website when suddenly everything jumps and you lose your place? Or worse, you&#8217;re about to tap a button and BAM, the page shifts and you click an ad instead? That&#8217;s exactly what Cumulative Layout Shift (CLS) measures. Think of CLS as a stability score for your website. It tracks how much [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":3990,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","footnotes":""},"categories":[10],"tags":[],"class_list":["post-3960","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-website-optimization"],"blocksy_meta":[],"uagb_featured_image_src":{"full":["https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cumulative-layout-shift.jpg",1000,612,false],"thumbnail":["https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cumulative-layout-shift-150x150.jpg",150,150,true],"medium":["https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cumulative-layout-shift-300x184.jpg",300,184,true],"medium_large":["https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cumulative-layout-shift-768x470.jpg",768,470,true],"large":["https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cumulative-layout-shift.jpg",1000,612,false],"1536x1536":["https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cumulative-layout-shift.jpg",1000,612,false],"2048x2048":["https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cumulative-layout-shift.jpg",1000,612,false],"trp-custom-language-flag":["https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cumulative-layout-shift-18x12.jpg",18,12,true],"betterdocs-category-thumb":["https:\/\/fastpixel.io\/wp-content\/uploads\/2025\/11\/cumulative-layout-shift-360x220.jpg",360,220,true]},"uagb_author_info":{"display_name":"Andrei Alba","author_link":"https:\/\/fastpixel.io\/fr\/blog\/author\/andreialba\/"},"uagb_comment_info":0,"uagb_excerpt":"Ever been reading a website when suddenly everything jumps and you lose your place? Or worse, you&#8217;re about to tap a button and BAM, the page shifts and you click an ad instead? That&#8217;s exactly what Cumulative Layout Shift (CLS) measures. Think of CLS as a stability score for your website. It tracks how much\u2026","_links":{"self":[{"href":"https:\/\/fastpixel.io\/fr\/wp-json\/wp\/v2\/posts\/3960","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fastpixel.io\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fastpixel.io\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fastpixel.io\/fr\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/fastpixel.io\/fr\/wp-json\/wp\/v2\/comments?post=3960"}],"version-history":[{"count":32,"href":"https:\/\/fastpixel.io\/fr\/wp-json\/wp\/v2\/posts\/3960\/revisions"}],"predecessor-version":[{"id":4023,"href":"https:\/\/fastpixel.io\/fr\/wp-json\/wp\/v2\/posts\/3960\/revisions\/4023"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/fastpixel.io\/fr\/wp-json\/wp\/v2\/media\/3990"}],"wp:attachment":[{"href":"https:\/\/fastpixel.io\/fr\/wp-json\/wp\/v2\/media?parent=3960"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fastpixel.io\/fr\/wp-json\/wp\/v2\/categories?post=3960"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fastpixel.io\/fr\/wp-json\/wp\/v2\/tags?post=3960"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}