Core Web Vitals: The Complete Guide
Master LCP, INP, and CLS — Google's page experience signals. Learn what causes poor scores and exactly how to fix them for better rankings.
Core Web Vitals (CWV) are Google's metrics for measuring real-world user experience: loading speed (LCP), interactivity (INP), and visual stability (CLS). They're a confirmed ranking signal and directly impact both conversions and search visibility.
The Three Core Web Vitals
Common Causes & Fixes
Poor LCP (Slow Loading)
- • Unoptimized hero images → Use WebP/AVIF + srcset + preload
- • Render-blocking CSS/JS → Inline critical CSS, defer non-critical
- • Slow server response → CDN, edge caching, faster hosting
- • Large DOM size → Reduce nesting, lazy-load below-fold content
Poor INP (Slow Interactivity)
- • Heavy JavaScript → Code-split, tree-shake, remove unused libraries
- • Long tasks blocking main thread → Break into smaller chunks
- • Third-party scripts → Lazy-load analytics, chat widgets, ads
- • Expensive event handlers → Debounce, use requestAnimationFrame
Poor CLS (Layout Jumping)
- • Images without dimensions → Always set width/height or aspect-ratio
- • Fonts causing FOUT → Use font-display: swap + preload fonts
- • Dynamic content injected above fold → Reserve space with min-height
- • Ads without reserved space → Set fixed container sizes
CWV Impact on Rankings
Core Web Vitals act as a tiebreaker in Google's algorithm. When two pages have similar relevance and authority, the one with better CWV wins. In competitive niches, this often means the difference between position #1 and position #5 — which translates to 3-5x more organic traffic.
Beyond rankings, CWV directly affects conversions. Amazon found that every 100ms of additional load time costs 1% of sales. For a site doing $1M/year, that's $10K per 100ms.
Check your Core Web Vitals score free — our scanner identifies exactly what's slowing your site and provides specific fixes.
Frequently Asked Questions
What replaced FID as a Core Web Vital?
INP (Interaction to Next Paint) replaced FID (First Input Delay) in March 2024. INP measures ALL interactions throughout the page lifecycle, not just the first one. It's a more comprehensive responsiveness metric.
Do Core Web Vitals matter for mobile AND desktop?
Google evaluates CWV separately for mobile and desktop. However, mobile is more important because Google uses mobile-first indexing. Fix mobile CWV first, then optimize desktop.
How do I test my Core Web Vitals?
Use PageSpeed Insights for lab data, Chrome UX Report (CrUX) for field data, or SAGIScan for a comprehensive audit that includes CWV alongside all other SEO/AI factors. Field data (real users) is what Google actually uses for rankings.
Can a WordPress site pass Core Web Vitals?
Yes, but it requires optimization. Common WordPress CWV killers: too many plugins, unoptimized themes, no caching, large images, render-blocking scripts. Our scan identifies exactly which elements are causing your WordPress site to fail.
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