Metrics
Cumulative Layout Shift (CLS)
Also: CLS
How much visible content unexpectedly shifts during a page lifetime.
Definition
A Core Web Vital. Measures the sum of all unexpected layout shifts during the lifespan of the page. Good < 0.1, needs improvement 0.1-0.25, poor > 0.25. Common causes: images without dimensions, late-loaded fonts, ad slots, banners that inject after first paint.
See also
More in Metrics
Largest Contentful Paint (LCP)
The render time of the largest content element visible in the viewport.
Interaction to Next Paint (INP)
Worst-case latency between a user input and the next visual update.
Time to First Byte (TTFB)
The time between request and the first byte of response from the origin or CDN.
Time to Interactive (TTI)
The time until the main thread is reliably free to handle user input.
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