The three metrics
Google’s Core Web Vitals focus on real-user experience:
- Largest Contentful Paint (LCP): how quickly the main content appears. Aim for 2.5 seconds or less.
- Interaction to Next Paint (INP): how quickly the page responds to input. Aim for 200 milliseconds or less.
- Cumulative Layout Shift (CLS): how much content jumps around while loading. Aim for 0.1 or less.
Improving LCP
Serve the hero image in a modern format at the right size, preload it, and avoid lazy-loading anything above the fold. Server-side rendering or static generation plus a CDN removes round trips before the first paint.
Improving INP
Long JavaScript tasks block the main thread. Ship less JavaScript, split bundles by route, defer third-party scripts and break heavy work into smaller chunks so the browser can respond to clicks and taps promptly.
Improving CLS
Reserve space for images, video and embeds with explicit dimensions or aspect ratios, load web fonts with sensible fallbacks, and never insert content above what the user is already reading.
Measure in the field
Lab tools are useful for debugging, but rankings use field data from real visitors. Monitor real-user metrics continuously so regressions are caught before they affect search visibility.
