Core Web Vitals
Google-defined user-experience metrics that assess loading performance, interaction responsiveness, and visual stability using real-world page data.
Core Web Vitals help teams identify performance problems that affect usability, conversion, accessibility, and search experience. They create shared targets across design, development, and SEO.
A team improves LCP by optimising the hero asset, reduces INP by removing long JavaScript tasks, and prevents CLS by reserving dimensions for media and fonts.
Core Web Vitals are not a complete measure of user experience or a guarantee of rankings. Lab and field data differ, thresholds may evolve, and good scores cannot compensate for irrelevant or inaccessible content.
The current metrics are Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness, and Cumulative Layout Shift for visual stability. Recommended thresholds at the 75th percentile are LCP within 2.5 seconds, INP below 200 milliseconds, and CLS below 0.1.
Experience Design, Systems Architecture
Google Search Central — Core Web Vitals — https://developers.google.com/search/docs/appearance/core-web-vitals; http://web.dev — https://web.dev/vitals/