What is Core Web Vitals?

Full Definition

Core Web Vitals are a set of user experience metrics that Google uses as a ranking signal. The three metrics are: (1) Largest Contentful Paint (LCP) — measures loading performance; the largest visible element should render in under 2.5 seconds. (2) Interaction to Next Paint (INP) — measures interactivity; pages should respond to user input in under 200ms. (3) Cumulative Layout Shift (CLS) — measures visual stability; unexpected layout shifts during loading should score below 0.1. These replaced First Input Delay (FID) in March 2024.

Why It Matters

Core Web Vitals became a confirmed Google ranking factor in 2021 and continue to be weighted in the Page Experience signal. Pages with poor Core Web Vitals scores are progressively demoted in rankings compared to pages with identical content but better UX. Additionally, faster, more stable pages have lower bounce rates and higher conversion rates—making CWV improvements doubly impactful.

How to Improve Your Core Web Vitals

1. 1

   Optimize LCP: preload your hero image, use a fast hosting provider, and enable caching; switching to Next.js with static generation significantly improves LCP

2. 2

   Fix INP: minimize JavaScript execution time, break up long tasks, and defer non-critical scripts

3. 3

   Fix CLS: always specify explicit width and height attributes on images, avoid inserting content above existing content after load, and use CSS min-height on dynamic elements

4. 4

   Use Google PageSpeed Insights and the CrUX report in Google Search Console to identify pages with poor field data scores

5. 5

   Enable compression (Brotli or Gzip) and serve images in next-gen formats (WebP, AVIF)

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