What are Core Web Vitals and how do they affect rankings?

Short answer
Core Web Vitals are three page experience metrics Google uses as a ranking signal: Largest Contentful Paint (LCP) measures loading speed, Interaction to Next Paint (INP) measures responsiveness to user input, and Cumulative Layout Shift (CLS) measures visual stability. Pages that score Good on all three benefit from a ranking boost, while Poor scores can hurt rankings and increase bounce rates. Google measures these using real-user data from Chrome browsers.

Core Web Vitals were introduced by Google in 2021 as part of the Page Experience update. They are not the most powerful ranking factor - content relevance and authority still dominate - but they act as a tiebreaker between pages that are otherwise evenly matched. More importantly, poor scores translate directly into worse user experience, which harms conversion rates and engagement metrics regardless of their ranking impact.

LCP (Largest Contentful Paint) should occur within 2.5 seconds. The largest content element on the page - usually a hero image or headline - should be visible quickly. Common causes of poor LCP include unoptimised images, render-blocking JavaScript, slow server response times, and missing preload hints for critical resources.

INP (Interaction to Next Paint), which replaced First Input Delay in March 2024, measures how fast the page responds to clicks, taps, and keyboard input throughout the entire session - not just the first interaction. Good is under 200ms. Heavy JavaScript main-thread work is the primary culprit.

CLS (Cumulative Layout Shift) measures unexpected movement of page elements. Ads that load after text, images without explicit dimensions, and dynamically injected content are the main offenders. Good CLS is under 0.1.

Google Search Console's Core Web Vitals report groups your URLs into Good, Needs Improvement, and Poor buckets based on CrUX data. Fix Poor pages first - they have the largest gap to close. A PageSpeed tool gives you per-URL diagnostics and actionable recommendations for each metric.

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Reviewed by Rameez Majeed · Last reviewed