LCP, CLS & INP Explained: The Core Web Vitals That Matter
A clear and beginner-friendly explanation of LCP, CLS, and INP — the three Core Web Vitals that determine real-world performance and rankings.
Google’s Core Web Vitals measure how fast, stable, and interactive your website feels to real users. They directly impact SEO rankings, user experience, and conversion rates. In this article, we break down the three most important metrics—LCP, CLS, and INP—and explain how to improve them with simple, effective techniques.
1. What is LCP (Largest Contentful Paint)?
LCP measures how long it takes for the main content of the page to appear. This is usually the hero image, headline, or large text block.
A good LCP is **under 2.5 seconds**.
Slow LCP happens due to:
• Large, unoptimized hero images • Render-blocking scripts • Slow server response times
**How to improve LCP:**
• Use Next.js `next/image` • Serve images in WebP/AVIF • Use Server Components to render HTML instantly • Enable CDN caching (Vercel, Cloudflare)
2. What is CLS (Cumulative Layout Shift)?
CLS measures how much content jumps around during load. These shifts frustrate users and cause mis-clicks.
A good CLS score is **under 0.1**.
Common causes:
• Images without width/height • Ads or embeds loading late • Fonts swapping after render
**How to improve CLS:**
• Always define image dimensions • Reserve space for dynamic components • Use `font-display: optional` or preload fonts
3. What is INP (Interaction to Next Paint)?
INP replaced FID as the interactivity metric. It measures how quickly the UI responds when a user clicks, taps, or interacts.
A good INP score is **under 200 ms**.
Bad INP usually comes from:
• Heavy JavaScript execution • Large client-side bundles • Long main-thread tasks
**How to improve INP:**
• Reduce client-side JavaScript • Move logic to server components • Lazy-load interactive widgets • Avoid heavy loops or computations in the browser
4. Why Core Web Vitals matter for SEO
Google uses Core Web Vitals as part of its ranking algorithm. Faster sites have:
• Higher visibility • Higher CTR • Better user engagement • Lower bounce rates
For performance-focused agencies like OpenMeta, Core Web Vitals are a core part of our development workflow.
5. Simple checklist to fix all three metrics
Here’s a quick checklist that improves LCP, CLS, and INP in one go:
• Use server components for content • Lazy-load non-critical client components • Optimize hero images & preload them • Define dimensions for images and embeds • Reduce JavaScript shipped to the client • Use CDN caching and edge rendering
Final thoughts
Core Web Vitals are not abstract metrics— they directly impact how users feel when they land on your site. By improving LCP, CLS, and INP, you ensure your website loads faster, feels stable, and responds instantly. At OpenMeta, our approach combines server rendering, optimized assets, and minimal JavaScript to consistently deliver top-tier Core Web Vital scores.