Core Web Vitals (2025): Complete Guide to Improve LCP, INP & CLS — Checklist + Fixes
Core Web Vitals (2025): Complete Guide to Improve LCP, INP & CLS — Checklist + Fixes
TL;DR
Core Web Vitals are Google’s user-experience metrics that influence search ranking and — more importantly — how real users perceive and interact with your site. In this guide you’ll learn what each metric measures, how to measure them, and 12 practical fixes (with code examples) you can implement right now to improve SEO, conversions and user satisfaction.
What are Core Web Vitals and why they matter?
Core Web Vitals (CWV) are a set of user-centered metrics focused on loading performance, interactivity, and visual stability. Google uses these as part of its page experience signals — so improving CWV helps both UX and your visibility in search results, though it’s not the only ranking factor. Use Search Console and field data to prioritize pages with the worst real-world scores.
The three Core Web Vitals (short definitions)
- LCP (Largest Contentful Paint): measures how long the main content (hero image, large text block) takes to load.
- INP (Interaction to Next Paint): measures responsiveness across the whole page (replaced FID in 2024). Focus on INP, not FID.
- CLS (Cumulative Layout Shift): measures unexpected layout shifts (ads, images without dimensions, dynamic content).
How to measure Core Web Vitals (tools & data sources)
Use a combination of field & lab tools:
- Google Search Console — Core Web Vitals report (field/CrUX aggregation).
- PageSpeed Insights / Lighthouse — lab + field suggestions.
- Chrome UX Report (CrUX) and WebPageTest for deeper diagnostics.
- Browser DevTools Performance tab for tracing long tasks & paints.
12 practical fixes (grouped by metric)
LCP — speed up the largest paint
1. Optimize images (size & format).Convert to WebP/AVIF, serve responsive `srcset` and lazy-load *below the fold*. Use `<link rel="preload" as="image" href="...">` for hero images.
2. Serve images from a fast CDN + enable HTTP/2 or HTTP/3. Reduce TTFB with edge caching and server tuning.
3. Preload critical assets (fonts, hero image, critical CSS). Example:
```html
<link rel="preload" as="image" href="/hero.webp">
<link rel="preload" as="font" href="/fonts/Inter.woff2" type="font/woff2" crossorigin>
