Core Web Vitals are a subset of Web Vitals that Google considers essential for delivering a great user experience. They are used as ranking signals in Google Search.
The three Core Web Vitals
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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.
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Interaction to Next Paint (INP) - Measures interactivity. To provide a good user experience, pages should have an INP of 200 milliseconds or less.
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Cumulative Layout Shift (CLS) - Measures visual stability. To provide a good user experience, pages should maintain a CLS of 0.1 or less.
Why Core Web Vitals matter
Since 2021, Core Web Vitals have been a ranking factor in Google Search. Pages that provide a better user experience (as measured by these metrics) may rank higher in search results.
How to measure Core Web Vitals
- Lab data: Tools like Lighthouse, PageSpeed Insights, and Chrome DevTools
- Field data: Chrome User Experience Report (CrUX), Real User Monitoring (RUM)
How VitalSentinel handles this
VitalSentinel tracks LCP, INP, and CLS from two sources: RUM Monitoring captures every real visit for instant regression alerts, while CrUX Monitoring pulls the same 28-day field dataset Google uses for ranking. When a deploy breaks your vitals, you find out in hours instead of waiting weeks for Google Search Console to update.
Related Terms
Cumulative Layout Shift (CLS)
A Core Web Vital that measures visual stability by quantifying how much page content unexpectedly shifts during loading.
Interaction to Next Paint (INP)
A Core Web Vital that assesses page responsiveness by measuring the latency of all user interactions throughout the page lifecycle.
Largest Contentful Paint (LCP)
A Core Web Vital that measures how long it takes for the largest content element visible in the viewport to render.
Page Experience
A set of signals that Google uses to measure how users perceive the experience of interacting with a web page beyond its pure information value.