Web Vitals

lastmod 2026-04-08created 2022-12-137 edits

Unified guidance on the quality signals considered essential to delivering a great user experience

Largest Contentful Paint (LCP)

Measures loading performance. To provide a good user experience, LCP should occur within 2.5 seconds of when the page first starts loading.

First Input Delay (FID)

Measures interactivity. To provide a good user experience, pages should have an FID of 100 milliseconds or less.

Cumulative Layout Shift (CLS)

• Cumulative Layout Shift (CLS) | Articles | web.dev

Measures visual stability. To provide a good user experience, pages should maintain a CLS of 0.1 or less.

Metric thresholds

• How to define Core Web Vitals metric thresholds | Articles | web.dev

See also

• JavaScript

Favorite site

• Web Vitals
  • (ko) Web Vitals
• Google Developers Korea Blog: Introducing Web Vitals: essential metrics for a healthy site
• Debugging Web Vitals on a real website :: Outsider's Dev Story
• History of Core Web Vitals | GeekNews