How to Improve Core Web Vitals: A Complete Guide for 2026

20 Aug 2026 13

What Are Core Web Vitals?

Core Web Vitals are a set of real-world performance metrics that Google uses as ranking signals. Since 2021, they are an official part of Google's Page Experience ranking system.

The three metrics are:

LCP (Largest Contentful Paint) — measures loading performance. Target: under 2.5 seconds.
CLS (Cumulative Layout Shift) — measures visual stability. Target: under 0.1.
INP (Interaction to Next Paint) — measures interactivity. Target: under 200ms.

How to Improve LCP

LCP is most commonly the hero image or the largest heading visible on screen. To improve it:

Serve images in WebP or AVIF format
Add fetchpriority="high" to your LCP image
Use a CDN close to your users
Enable server-side compression (gzip or brotli)
Preload critical resources with <link rel="preload">

How to Fix CLS

Layout shifts happen when elements move unexpectedly. The most common causes:

Images without explicit width and height attributes
Ads or embeds without reserved space
Web fonts that cause FOUT (Flash of Unstyled Text)

Fix: always add width and height to every <img> tag. Use font-display: swap for web fonts.

How to Improve INP

INP replaced FID in March 2024. It measures how fast the page responds to all user interactions. To improve it:

Break up long JavaScript tasks (over 50ms)
Defer non-critical scripts
Use requestIdleCallback for non-urgent work
Minimize third-party script impact

How to Measure Core Web Vitals

Use these tools to audit your scores:

Google PageSpeed Insights — shows real-user data (CrUX) and lab data
Google Search Console — Core Web Vitals report by page group
Chrome DevTools — Performance panel for local testing
Optyxo SEO Audit — instant audit including performance score and CWV data

Quick Wins Checklist

✅ Add width and height to all images
✅ Convert images to WebP
✅ Add loading="lazy" to below-fold images
✅ Add fetchpriority="high" to the hero image
✅ Minify CSS and JavaScript
✅ Enable gzip/brotli compression
✅ Use a CDN
✅ Defer render-blocking scripts

Run a free audit on Optyxo to see your current Core Web Vitals score and get specific recommendations for your website.