Core Web Vitals

Definition

Core Web Vitals are Google's three key metrics for user experience on the web: Largest Contentful Paint (loading speed), First Input Delay (interactivity), and Cumulative Layout Shift (visual stability). They're used as ranking signals in Google Search.

Simple Explanation

Core Web Vitals measure what actually matters to users: 'Did this page load fast?', 'Can I click things right away?', 'Did anything jump around while I was reading?' Good UX isn't subjective — these three numbers quantify it.

Real-World Use Case

An e-commerce site sees Core Web Vitals drop after a redesign. Developers use Lighthouse and Web Vitals extension to identify that a new banner is causing layout shift and slow LCP.

Examples

Related Terms

Learn More

• web.dev/vitals
• Google Search Central — Core Web Vitals