🔍 Check Current Page Performance
Measure Core Web Vitals metrics for the current page, including LCP, FID, CLS, INP, and TTFB. Get optimization tips based on results.
🔒All measurements happen locally. No data is uploaded to any server.
Pure Frontend · LCP/FID/CLS/INP/TTFB · Performance Optimization Tips
Zero Dependencies · Works OfflineMeasure Core Web Vitals metrics for the current page, including LCP, FID, CLS, INP, and TTFB. Get optimization tips based on results.
The Web Vitals Checker is a pure frontend online tool for measuring Core Web Vitals performance metrics. Core Web Vitals are a set of key metrics defined by Google that directly impact search rankings. The tool measures LCP (Largest Contentful Paint), INP (Interaction to Next Paint), CLS (Cumulative Layout Shift) as the three core metrics, plus FID (First Input Delay) and TTFB (Time to First Byte) as supplementary metrics, and provides targeted optimization tips based on results.
Step 1: Click "Run Check" button. The tool automatically measures the current page's performance metrics.
Step 2: View results. Each metric shows its value and rating (Good / Needs Improvement / Poor).
Step 3: Review optimization tips and improve page performance accordingly.
Step 4: Click "Export Report" to save results, or use Ctrl+Shift+C shortcut to copy.
Core Web Vitals are a Google search ranking factor. Measure and optimize these metrics to improve search rankings and organic traffic.
Regularly check page performance metrics, monitor for regressions, and quickly identify and fix performance issues.
Compare your site's Core Web Vitals against competitors to find performance gaps and optimization opportunities.
Check performance metrics before deploying new features to ensure no performance regressions are introduced.
Core Web Vitals were introduced by Google in 2020 and became an official search ranking factor in 2021. The three core metrics cover loading (LCP), interactivity (INP), and visual stability (CLS). In March 2024, INP replaced FID as a core metric because INP measures the responsiveness of all interactions, while FID only measures the first. Key optimizations: LCP - reduce critical resource loading time (optimize images with WebP/AVIF, use CDN, preload critical resources, reduce server response time). INP - reduce main thread blocking (code splitting, reduce JS execution time, use Web Workers). CLS - ensure layout stability (set image/video dimensions, avoid dynamic content insertion, use font-display: swap).
Core Web Vitals are a set of key performance metrics defined by Google, including LCP (Largest Contentful Paint), INP (Interaction to Next Paint), and CLS (Cumulative Layout Shift), used to measure user experience quality.
LCP of 2.5 seconds or less is good (green), 2.5-4 seconds needs improvement (orange), and over 4 seconds is poor (red). LCP measures how quickly the main content loads.
Set explicit width and height for images/videos, avoid dynamically inserting content above the viewport, use CSS contain property, pre-allocate ad slot space, and avoid unstable fonts.
FID only measures first interaction delay, while INP measures the latency of all interactions. INP replaced FID as a Core Web Vitals metric in March 2024, providing a more comprehensive view of interactivity.
No. All measurements happen locally in your browser. Only the current page's performance metrics are measured, and no data is sent to any server.
TTFB (Time to First Byte) is the time the browser waits from making a request to receiving the first byte from the server. It reflects server response speed. TTFB of 800ms or less is good.