By Sply Code | July 3, 2025
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📊 Google Core Web Vitals: What They Are and How to Improve Them
Google wants to rank websites that deliver a great user experience. That’s why they introduced Core Web Vitals — a set of performance metrics that directly affect your website’s ranking.
If you want your site to appear higher in Google search results, understanding and improving Core Web Vitals is essential.
In this post, you'll learn what Core Web Vitals are, why they matter, and how to improve them step by step.
✅ What Are Google Core Web Vitals?
Core Web Vitals are a set of three key performance metrics that measure how users experience your website in real time.
| Metric |
What It Measures |
Good Score |
| LCP (Largest Contentful Paint) |
Loading speed |
≤ 2.5 seconds |
| FID (First Input Delay) |
Interactivity |
≤ 100 ms |
| CLS (Cumulative Layout Shift) |
Visual stability |
≤ 0.1 |
These are part of Google's Page Experience update and are now an official SEO ranking factor.
1️⃣ Largest Contentful Paint (LCP)
What it is: Measures how long it takes for the largest visible content (image, text, video) to appear on screen.
🔧 How to improve LCP:
- Use faster hosting
- Optimize and compress large images
- Implement lazy loading
- Use a CDN to reduce server distance
- Remove unnecessary render-blocking scripts
2️⃣ First Input Delay (FID)
What it is: Measures the time between a user’s first interaction (like clicking a button) and when the browser responds.
🔧 How to improve FID:
- Minimize JavaScript execution time
- Use code splitting (only load what's needed)
- Remove unused third-party scripts
- Use web workers for background processing
📝 Note: For testing purposes, Google now uses INP (Interaction to Next Paint) instead of FID. But improving FID still benefits responsiveness.
3️⃣ Cumulative Layout Shift (CLS)
What it is: Measures how much elements unexpectedly shift while the page loads.
🔧 How to improve CLS:
- Set fixed width and height for images and ads
- Don’t insert content above existing content dynamically
- Avoid using fonts that cause layout jumps (FOIT/FOUT)
- Preload important fonts and icons
🧪 How to Check Your Core Web Vitals
Use these free tools to test and monitor your Core Web Vitals:
Each tool provides insights and suggestions based on real user data (field data) and lab data (simulated).
🛠 Additional Optimization Tips
- ✅ Use modern image formats: WebP or AVIF
- ✅ Minify and defer JavaScript and CSS
- ✅ Enable GZIP or Brotli compression
- ✅ Reduce third-party scripts (like ads, chat widgets)
- ✅ Avoid too many fonts or heavy animations
🚀 Why Core Web Vitals Matter for SEO
- Direct ranking factor in Google Search
- Improve user satisfaction and time on site
- Reduce bounce rate an
