What Are Core Web Vitals?
Core Web Vitals are a set of metrics Google uses to measure the real-world experience of loading a page. They've been official ranking signals since 2021 — alongside existing signals like mobile-friendliness and HTTPS.
The Three Metrics
LCP (Largest Contentful Paint): how long the main content takes to load. Aim under 2.5 seconds.
INP (Interaction to Next Paint): how quickly the page responds when someone clicks or taps. Aim under 200 milliseconds.
CLS (Cumulative Layout Shift): how much the page layout jumps around while loading. Aim under 0.1.
Why Speed Affects SEO
Google's goal is to rank pages people enjoy. A slow, jumpy page makes users leave — so Google uses Core Web Vitals as a tiebreaker and ranking factor, especially on mobile where connections are weaker. Fast pages also convert better, so the SEO benefit is doubled.
What Hurts Your Scores
Large, unoptimized images
Slow servers and no CDN
Too much JavaScript and third-party scripts
Layout elements that shift as fonts and images load
How to Check Yours
Run PageSpeed Insights or open Google Search Console's Core Web Vitals report. Both show your scores for real users and give concrete fixes for each problem.
The Bottom Line
Core Web Vitals are Google's way of measuring what users already feel: speed and stability. Improve them and you improve rankings, user experience, and conversions all at once.