Cumulative Layout Shift (CLS)

Cumulative Layout Shift (CLS) is one of the three Core Web Vitals and a key measure of how visually stable your site feels. At Uxify, we use CLS as a critical checkpoint for diagnosing disruptive layout shifts during page load and interaction.
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CLS captures how much visible content moves around the screen unexpectedly. This could be a button jumping out of place or a headline shifting as fonts load. These shifts are not just annoying - they directly impact user trust and experience.
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To deliver a stable experience, the 75th percentile (P75) of Cumulative Layout Shift (CLS) should be under 0.1. This means 75% of your real users experience minimal layout shift. Below is how Uxify categorizes CLS performance:

Two words: users and Google. Let’s start with your users. Ever tried to tap a button, only for it to shift at the last second and cause a misclick? That’s CLS at work - and it frustrates users more than you'd expect. A low CLS makes your interface feel stable and polished, which builds trust and improves conversions.
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Then there's Google. CLS is part of its Core Web Vitals scoring, meaning it's baked right into how search rankings are influenced. A jittery, unstable layout can lower your credibility - and your visibility. So yes, fixing CLS is about looking good and being found.

Real User CLS is collected from every single pageview on your site via the Uxify script - with zero sampling. That means you get a complete picture of layout stability issues across all pages, devices, user types, and geographies. Unlike CrUX data, which only samples from a subset of users, this dataset captures the full spectrum of layout shifts caused by real-world interactions like late-loading images, dynamically injected banners, or web fonts kicking in. It’s the most accurate source for identifying and resolving layout instability across your entire site.

This filter takes your Real User CLS dataset and narrows it down to just the URLs that are recognized in Google’s Chrome UX Report. Why? Because those URLs are the ones that Google includes in Core Web Vitals scoring - and ultimately, in your SEO rankings. By isolating these URLs, you can directly compare how your actual layout shift performance stacks up against what Google sees. It’s especially useful when you want to debug why your CrUX scores don’t reflect the improvements you’ve made elsewhere on your site.

Google CrUX CLS is based on real-user data collected directly from Chrome browsers, aggregated into public datasets on a weekly basis. It’s limited to high-traffic pages and anonymized users, meaning it doesn’t cover your whole site - but it’s what Google uses for Core Web Vitals in Search Console and rankings. This makes it a critical reference point. If you’re optimizing for SEO performance, monitoring CrUX CLS alongside your Real User data helps ensure that your efforts are actually being picked up by Google.

Here are three of the most common and actionable reasons we see for high CLS in Uxify Experience:

You can use 80+ CLS lenses in Uxify Experience to find your website’s top layout offenders. It’s all displayed in a single dashboard view, so you can spot patterns instantly. Once identified, you can stabilize your layout and eliminate shift anxiety using Navigation AI.