What is Core Web Vitals?
Core Web Vitals are a set of metrics that Google introduced as ranking factors in 2021. They measure the actual user experience on a website in three areas: Largest Contentful Paint (LCP) measures the loading speed of the largest visible element, First Input Delay (FID) or Interaction to Next Paint (INP) measures responsiveness to user interactions, and Cumulative Layout Shift (CLS) measures visual stability during loading. Good Core Web Vitals are not only important for SEO but also improve conversion rates and user satisfaction. The metrics can be measured in Google Search Console, PageSpeed Insights, and Chrome DevTools.
Key Points
- LCP (Largest Contentful Paint): Should be under 2.5 seconds
- INP (Interaction to Next Paint): Should be under 200ms
- CLS (Cumulative Layout Shift): Should be under 0.1
- Image optimization is often the biggest lever for LCP
- JavaScript optimization improves INP
- Reserved placeholders prevent layout shifts
Practical Example
“After optimizing Core Web Vitals, LCP improved from 4.2s to 1.8s and ranking increased by 8 positions.”