What are Web Vitals?
Web Vitals are a set of standardized metrics defined by Google that measure real-world user experience on web pages. The Core Web Vitals subset — LCP, INP, and CLS — are ranking factors in Google search and focus on loading performance, interactivity, and visual stability.
How Does Web Vitals Work?
The three Core Web Vitals are: Largest Contentful Paint (LCP), which measures how long it takes for the largest visible element to render and should be under 2.5 seconds; Interaction to Next Paint (INP), which measures responsiveness to user interactions and should be under 200 milliseconds; and Cumulative Layout Shift (CLS), which measures visual stability by quantifying unexpected layout shifts and should be below 0.1. These metrics are collected from real Chrome users through the Chrome User Experience Report (CrUX).
Improving Web Vitals requires attention to both server and client performance. LCP is improved by optimizing server response times (TTFB), preloading critical resources, and using efficient image formats. INP is improved by minimizing JavaScript execution time, breaking up long tasks, and reducing main thread blocking. CLS is improved by setting explicit dimensions for images and ads, avoiding dynamic content injection above the fold, and using CSS containment. Web hosting choices directly impact Web Vitals through server response times, geographic proximity via CDN, and HTTP protocol support.