Definition

Core Web Vitals are a Google-defined set of three field metrics — Largest Contentful Paint (LCP), Interaction to Next Paint (INP) and Cumulative Layout Shift (CLS) — used to measure a page's loading performance, responsiveness to input, and visual stability.

Google measures Core Web Vitals from real user data collected via the Chrome User Experience Report. LCP gauges how long the largest content element takes to render. INP gauges the latency between a user's interaction and the next visual update. CLS gauges how much visible content shifts unexpectedly during the page's life. Google has stated Core Web Vitals are one of many ranking signals; pages that meet the thresholds tend to perform better in search but the metrics alone do not determine ranking.

Examples

• Reading the metrics in Search Console

  A site's Core Web Vitals report flags 12 URLs with poor INP. The dev team fixes a large blocking JavaScript handler, the next 28-day collection window shows the URLs move to 'good', and Search Console marks them as passing.

• Targeting the thresholds

  To pass, 75% of page loads should hit LCP ≤ 2.5s, INP ≤ 200ms, and CLS ≤ 0.1 at the 75th percentile of users.

Sources

• Google Search Central — Understanding Core Web Vitals
• web.dev — Core Web Vitals

Related terms

• Schema Markup
  Structured data added to a page that describes its content to search engines in a machine-readable format.

Where QueryCatch uses this

• SEO Audit
• Page Optimisation