CLS (Cumulative Layout Shift).
CLS is one of Google's three Core Web Vitals and measures the visual stability of a page. It quantifies how much elements shift during loading — e.g., a button that suddenly jumps to a different position. A CLS value below 0.1 is considered 'good'.
CLS (Cumulative Layout Shift) — Explained in Detail
CLS (Cumulative Layout Shift) is one of Google's three Core Web Vitals and measures the visual stability of a web page. The CLS score quantifies how much visible elements shift during page load — for example, when an image loads late and pushes a button down that the user was about to click. A CLS value below 0.1 is considered 'good', 0.1–0.25 as 'needs improvement', and above 0.25 as 'poor'.
Visual instability is not just annoying for users — it has been a direct Google ranking factor since 2021. Common causes of a high CLS: images without defined width/height attributes (the browser doesn't know how much space to reserve), late-loading ads, web fonts that jump during loading (Flash of Invisible Text / Flash of Unstyled Text), and dynamically inserted content above existing content.
Measures to improve CLS: Always set width and height attributes for images and videos. Reserve space for ads and embedded content. Load web fonts with `font-display: optional` or `swap`. Avoid inserting new content above existing content. At DLM Digital, CLS optimizations are part of every web design project — by default.
Related Page
Core Web VitalsFrequently Asked Questions About CLS (Cumulative Layout Shift)
You can measure CLS in Google PageSpeed Insights (pagespeed.web.dev), Google Search Console (Core Web Vitals Report), and Chrome DevTools (Lighthouse audit). For field measurement (real user data), use the Core Web Vitals Report in Search Console — this shows how real users experience your site.
Common causes: images without width/height attributes, late-loading ads, web fonts without font-display settings, dynamically inserted banners or cookie notices above the main content, and lazy-loaded content without placeholder dimensions.
Yes. Since the Page Experience Update in 2021, all three Core Web Vitals (LCP, FID/INP, CLS) are direct Google ranking factors. A good CLS value improves not only the user experience but also affects organic rankings — especially on mobile devices.
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