Core Web Vitals: LCP, INP and CLS Explained

Core Web Vitals are Google's standard for user experience and a confirmed ranking factor since 2021.

The three metrics

Largest Contentful Paint (LCP) measures how quickly the largest visible content block loads. Good: under 2.5 seconds. Needs improvement: 2.5-4 seconds. Poor: over 4 seconds. Optimization: compress images (AVIF/WebP), reduce server response time, eliminate render-blocking resources.

Interaction to Next Paint (INP) measures response time to user interactions (clicks, taps, keyboard inputs). Good: under 200ms. Needs improvement: 200-500ms. Poor: over 500ms. INP replaced FID in March 2024 and is significantly more demanding. Optimization: reduce JavaScript execution time, break up long tasks, use web workers.

Cumulative Layout Shift (CLS) measures visual stability — how much elements shift during loading. Good: under 0.1. Needs improvement: 0.1-0.25. Poor: over 0.25. Optimization: specify dimensions for images and ads, preload fonts (font-display: swap), placeholders for dynamic content.

CWV and Ranking

Core Web Vitals are a confirmed ranking factor, but primarily act as a tie-breaker. For pages with similar content, better user experience can make the difference. The estimated influence is 10-15 percent.

CWV and AI Crawlers

AI crawlers have tight timeouts of 1-5 seconds. A slow website risks AI crawlers not being able to fully load the page. Good CWV values are therefore also relevant for SGE visibility.