Understanding Core Web Vitals

What are Core Web Vitals?

Core Web Vitals are Google's key metrics for measuring user experience. They directly affect your search rankings.

The Three Metrics

Metric	Measures	Good
LCP	Loading speed	< 2.5s
INP	Interactivity	< 200ms
CLS	Visual stability	< 0.1

LCP — Largest Contentful Paint

Time for the biggest element (image/text) to load. Improve by optimizing images and server response.

INP — Interaction to Next Paint

How fast the page responds to clicks/taps. Improve by reducing heavy JavaScript.

CLS — Cumulative Layout Shift

How much elements jump around while loading. Fix by setting image/video dimensions.

<!-- Prevents layout shift -->
<img src="x.jpg" width="800" height="600" alt="...">

How to Measure

Use Lighthouse, PageSpeed Insights, or the Chrome Web Vitals extension.

FAQs

Do Core Web Vitals affect SEO?

Yes — they're a Google ranking factor. More in our Performance guides.

What replaced FID?

INP replaced FID (First Input Delay) in 2024 as the interactivity metric.