What is CLS (Cumulative Layout Shift)?
A metric measuring how much page content unexpectedly moves around while loading.
Why It Matters
Layout shifts frustrate users, especially when they accidentally click the wrong thing because content moved.
Real-World Example
An ad loading above the article and pushing the text down just as you are about to click a link.
“Understanding terms like CLS (Cumulative Layout Shift) matters because it helps you have better conversations with developers and make smarter decisions about your software. You do not need to be technical. You just need to know enough to ask the right questions.”
Related Terms
Core Web Vitals
Google's three key metrics for measuring page loading speed, interactivity, and visual stability.
LCP (Largest Contentful Paint)
A metric measuring how long it takes for the largest visible content element to finish loading.
INP (Interaction to Next Paint)
A metric measuring the overall responsiveness of a page to user interactions throughout its lifetime.
Web Vitals
A set of metrics from Google that measure real-world user experience on web pages.
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Related Terms
Web Vitals
A set of metrics from Google that measure real-world user experience on web pages.
Core Web Vitals
Google's three key metrics for measuring page loading speed, interactivity, and visual stability.
LCP (Largest Contentful Paint)
A metric measuring how long it takes for the largest visible content element to finish loading.
INP (Interaction to Next Paint)
A metric measuring the overall responsiveness of a page to user interactions throughout its lifetime.
Cache
A temporary storage that keeps copies of frequently accessed data for faster retrieval
CDN
A network of servers around the world that stores copies of your content closer to users