Cumulative Layout Shift (CLS) measures the visual stability of a page by quantifying how much the visible content shifts during loading. It scores unexpected layout shifts caused by images without dimensions, dynamically injected content, web fonts, and ads. Target: under 0.1.
Why CLS (Cumulative Layout Shift) matters for SEO
High CLS creates a frustrating user experience where buttons move as you try to click them, text jumps around, and content shifts unexpectedly. This increases accidental clicks and bounce rate. CLS is scored site-wide since the March 2026 update.
Pro tip on CLS (Cumulative Layout Shift)
Set explicit width and height on all images and videos. Preload web fonts. Reserve space for ads and dynamic content. Avoid inserting content above existing content. Use CSS contain to isolate layout shifts.
Related terms
Layout shifts frustrate users and hurt rankings. CrawlRaven identifies pages with high CLS and the specific elements causing shifts.
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