Mastering Core Web Vitals: The 2025 Performance Optimization Guide

Core Web Vitals in 2025

Google's Core Web Vitals remain crucial ranking factors. In 2024, INP (Interaction to Next Paint) replaced FID as a core metric, emphasizing sustained interactivity over first input.

The Three Pillars

LCP (Largest Contentful Paint): Target < 2.5s

INP (Interaction to Next Paint): Target < 200ms

CLS (Cumulative Layout Shift): Target < 0.1

LCP Optimization

Optimize and compress images (WebP, AVIF)

Implement priority hints for critical resources

Use CDN for static assets

Preload critical fonts and images

Server-side render above-the-fold content

INP Optimization

Break up long tasks (yield to main thread)

Use web workers for heavy computation

Optimize event handlers

Implement virtualization for long lists

CLS Optimization

Always specify image dimensions

Reserve space for dynamic content

Avoid inserting content above existing content

Use CSS transform for animations

Measurement Tools

Use Lighthouse, PageSpeed Insights, and Chrome DevTools for continuous monitoring.