Core Web Vitals & User Experience Signals
Google’s ranking algorithm increasingly prioritizes user experience. Core Web Vitals are a set of specific performance metrics that help measure how users perceive the speed, responsiveness, and stability of your website. These signals directly affect your SEO performance.
What Are Core Web Vitals?
Google defines three key Core Web Vitals:
Largest Contentful Paint (LCP)
Measures loading performance. Aim for LCP under 2.5 seconds.
First Input Delay (FID) (replaced by INP in 2024)
Measures interactivity. Google now uses Interaction to Next Paint (INP) — should be under 200ms.
Cumulative Layout Shift (CLS)
Measures visual stability. Target a CLS score of less than 0.1.
Additional UX Signals Considered by Google
Besides Core Web Vitals, other user experience signals matter for SEO:
- Mobile-Friendliness
- Safe Browsing (no malware)
- HTTPS Security
- No Intrusive Interstitials (e.g., pop-ups that block content)
- Page engagement (like bounce rate, time on site — indirectly)
Why These Metrics Matter
- Google uses them as part of its Page Experience ranking signal
- Poor scores can lower rankings even if content is good
- Better UX = happier visitors = higher conversion rates
Tools to Measure Core Web Vitals
- Google PageSpeed Insights
- Google Search Console (Page Experience Report)
- Lighthouse (via Chrome DevTools)
- Web.dev
- GTmetrix
How to Improve Core Web Vitals
Improve LCP:
- Optimize images (use WebP or AVIF)
- Use fast, reliable hosting (e.g. CDN)
- Minimize render-blocking resources
Improve INP (formerly FID):
- Reduce JavaScript execution time
- Break up long tasks
- Use modern frameworks responsibly
Improve CLS:
- Set width/height for images and ads
- Avoid layout shifts from late-loading fonts or UI elements
Core Web Vitals are not just technical metrics—they reflect how real users experience your site. Optimizing these signals is essential for long-term SEO success and better visitor satisfaction.