Core Web Vitals 2025: Complete Guide to Optimize Performance

What Are Core Web Vitals?

Core Web Vitals are three key metrics that Google uses to measure user experience:

1. LCP (Largest Contentful Paint) - How quickly the main content loads
2. FID (First Input Delay) - How responsive your site is to user interaction
3. CLS (Cumulative Layout Shift) - How stable your layout is during loading

Why They Matter

Google has made Core Web Vitals a ranking factor. Sites with good vitals rank higher in search results and provide better user experience.

How to Improve Each Metric

Improving LCP

• Optimize images and videos
• Minimize CSS and JavaScript
• Use a Content Delivery Network (CDN)
• Implement lazy loading

Improving FID

• Reduce JavaScript execution time
• Break up long tasks
• Use web workers for heavy computations
• Defer non-critical JavaScript

Improving CLS

• Avoid layout shifts by specifying image dimensions
• Use transform animations instead of position changes
• Avoid inserting content above existing content
• Use font-display: swap for web fonts

Tools to Measure

• Google PageSpeed Insights - Free, comprehensive analysis
• Lighthouse - Built into Chrome DevTools
• WebPageTest - Detailed waterfall analysis
• Sentry - Real user monitoring

Action Plan

1. Measure your current vitals
2. Identify the biggest bottlenecks
3. Implement optimizations
4. Monitor improvements
5. Iterate and refine

Start improving your Core Web Vitals today!