Poor CLS

CLS measures how much the page jumps as it loads. High CLS makes pages feel unstable and causes misclicks.

What it is

This check flags pages with a Cumulative Layout Shift above the recommended threshold (good is under 0.1).

Why it matters for SEO

CLS is a Core Web Vital and ranking signal; visual instability frustrates users and hurts conversions.

Example

CLS - 0.32   (good: < 0.1)

How to fix

1. Set explicit width/height (or aspect-ratio) on images and embeds.
2. Reserve space for ads, banners, and late-loading content.
3. Avoid inserting content above existing content; preload fonts.
4. Re-test after changes.

Related checks

• Heavy page
• Poor INP
• Poor LCP
• Privacy-friendly analytics & real-user Core Web Vitals

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