The three Core Web Vitals metrics
Largest Contentful Paint (LCP) measures how long it takes for the largest visible content element on the page to load. It reflects perceived load speed.
- Good: under 2.5 seconds
- Needs improvement: 2.5 to 4.0 seconds
- Poor: over 4.0 seconds
Interaction to Next Paint (INP) measures the responsiveness of a page to user interactions such as clicks, taps, and keyboard input. It replaced First Input Delay (FID) as a Core Web Vital in March 2024.
- Good: under 200 milliseconds
- Needs improvement: 200 to 500 milliseconds
- Poor: over 500 milliseconds
Cumulative Layout Shift (CLS) measures visual stability — how much page elements shift unexpectedly during loading. A high CLS score indicates elements are moving around as the page loads.
- Good: under 0.1
- Needs improvement: 0.1 to 0.25
- Poor: over 0.25
How to measure Core Web Vitals
Core Web Vitals can be measured using:
- PageSpeed Insights (pagespeed.web.dev) — lab and field data for any URL
- Google Search Console — Core Web Vitals report with real user data across the entire site
- Chrome DevTools — Lighthouse tab for lab measurements
- CrUX (Chrome User Experience Report) — aggregate field data
Core Web Vitals and SEO
Google confirmed Core Web Vitals as a ranking signal as part of the Page Experience update. While content quality and relevance remain the primary ranking factors, Core Web Vitals can be a tiebreaker between pages of similar quality.
Core Web Vitals and AI Search
Core Web Vitals are not a confirmed citation signal for AI Search systems. However, page performance affects crawlability and overall discoverability — slow pages are less likely to be fully crawled and indexed, which indirectly affects AI Search visibility.
Grupa Insight implementation example
Grupa Insight's own website scores 99/100 in PageSpeed Insights on mobile with LCP at 2.1s, CLS at 0, and TBT at 50ms. The site is built on Next.js 14 with server-side rendering, deployed on Vercel, with image optimization via next/image and no render-blocking resources. This is the same technical stack and approach the agency implements for client projects.
Source
Core Web Vitals are documented at web.dev/explore/metrics and in Google Search Central at developers.google.com/search/docs/appearance/core-web-vitals