What are Core Web Vitals?
TL;DR
Core Web Vitals are three metrics defined by Google — LCP, INP, and CLS — that measure loading speed, interactivity, and visual stability of web pages.
Last updated: 2026-03-09
Definition#
Core Web Vitals are a set of three metrics that Google uses to measure real-world user experience on web pages.
LCP (Largest Contentful Paint) measures loading performance. It tracks how long it takes for the largest visible element (image, text block, or video) to fully render. Good: under 2.5 seconds.
INP (Interaction to Next Paint) measures interactivity. It tracks how quickly the page responds when a user clicks, taps, or types. Good: under 200 milliseconds.
CLS (Cumulative Layout Shift) measures visual stability. It tracks how much the page layout shifts unexpectedly during loading. Good: under 0.1.
These metrics are measured using real user data (Chrome User Experience Report) and lab data (Lighthouse, PageSpeed Insights).
Why It Matters for AI Readiness#
Fast, stable pages are easier for AI crawlers to process. Poor Core Web Vitals can signal low quality to search engines, which indirectly affects your AI visibility. The AgentReady™ scanner evaluates performance through the Speed & Performance factor.
For optimization tips, see How to Improve Page Speed.
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