Core Web Vitals remain Google's primary user experience signal for search ranking. In 2026, the metrics have evolved, and understanding exactly what Google measures — and how to optimize — is critical for any website.
Largest Contentful Paint (LCP) measures when the main content of a page becomes visible. The target is under 2.5 seconds. The most common LCP elements are hero images, heading text, and video thumbnails.
Optimizing LCP: preload critical resources (fonts, hero images), use responsive images with proper srcset, implement server-side rendering for above-the-fold content, and eliminate render-blocking CSS/JS. Our sites consistently achieve LCP under 1.5 seconds.
Interaction to Next Paint (INP) replaced First Input Delay in 2024 and measures overall page responsiveness. INP tracks the latency of all interactions (clicks, taps, key presses) throughout the page lifecycle, not just the first input.
Optimizing INP: break long tasks into smaller chunks using requestIdleCallback or scheduler.yield(), minimize main thread blocking, use web workers for heavy computations, and implement optimistic UI updates. Target: under 200ms for all interactions.
Cumulative Layout Shift (CLS) measures visual stability — how much content shifts unexpectedly during loading. The target is under 0.1. Common culprits: images without dimensions, dynamically injected content, and web fonts causing text reflow.
Optimizing CLS: always specify width and height on images and videos, use CSS aspect-ratio for responsive containers, preload web fonts with font-display: swap, and reserve space for dynamic content using skeleton screens.
The new Time to First Byte (TTFB) isn't technically a Core Web Vital but strongly influences LCP. Google recommends under 800ms. Server-side optimizations, CDN deployment, and edge rendering are the primary levers.
Monitoring is essential. Use Google Search Console's Core Web Vitals report for field data, PageSpeed Insights for lab data, and web-vitals JavaScript library for real-user monitoring (RUM). Fix issues by impact, starting with the pages that receive the most organic traffic.