Core Web Vitals Checker
Analyze your page experience in minutes. Measure LCP, INP, and CLS, identify render-blocking resources, and fix speed bottlenecks to drive more organic traffic.
Core Web Vitals Analysis Report
Website:
LCP (Loading)
-
Waiting...INP (Interactivity)
-
Waiting...CLS (Stability)
-
Waiting...Performance Score
-
Waiting...Performance Issues Detected
| Priority | Performance Issue | Impact | Metric Affected |
|---|
Web Vitals Diagnostic Overview
These metrics represent your page experience score. Passing all three Core Web Vitals is critical for Google rankings and ensures a smooth, fast experience for your visitors.
Analyzing 25,000+ Performance Tests Every Month
Join thousands of developers and SEOs optimizing their page speed for better rankings.
Stop Losing Rankings to Slow Pages
Stop guessing why your site failed the Page Experience update. Our tool analyzes your site's performance bottlenecks to prevent slow load times and layout shifts from ruining your user experience.
Complete Web Performance Suite
Everything you need to measure, debug, and optimize your page experience
LCP Optimizer
Analyze your rendering path and identify the exact hero element slowing down your Largest Contentful Paint.
INP Debugger
Find heavy JavaScript execution and long main-thread tasks that delay your Interaction to Next Paint.
CLS Visualizer
Highlight elements that shift during page load to fix visual instability and improve Cumulative Layout Shift.
CrUX Data Fetcher
Extract real-world user experience data from the Chrome User Experience Report directly for your URLs.
Lighthouse Auditor
Run simulated mobile and desktop performance tests in a controlled environment to benchmark improvements.
Waterfall Analyzer
Visualize your asset loading sequence to spot third-party scripts blocking your main thread.
Mobile Simulator
Test your page speed over simulated 3G and 4G connections to ensure performance for all users.
Performance Reports
Export branded PDF reports outlining Core Web Vitals optimization opportunities for your clients.
LCP Optimizer
Analyze your rendering path and identify the exact hero element slowing down your Largest Contentful Paint.
INP Debugger
Find heavy JavaScript execution and long main-thread tasks that delay your Interaction to Next Paint.
CLS Visualizer
Highlight elements that shift during page load to fix visual instability and improve Cumulative Layout Shift.
CrUX Data Fetcher
Extract real-world user experience data from the Chrome User Experience Report directly for your URLs.
Lighthouse Auditor
Run simulated mobile and desktop performance tests in a controlled environment to benchmark improvements.
Waterfall Analyzer
Visualize your asset loading sequence to spot third-party scripts blocking your main thread.
Mobile Simulator
Test your page speed over simulated 3G and 4G connections to ensure performance for all users.
Performance Reports
Export branded PDF reports outlining Core Web Vitals optimization opportunities for your clients.
Measure Web Vitals in 3 Steps
The fast way to ensure your pages deliver a top-tier user experience
Enter Your URL
Paste the webpage you want to test. Our system will initialize headless browsers to simulate user interactions and load patterns.
Analyze Metrics
We compile data on LCP, INP, and CLS, combining simulated lab data with historical 28-day field data from Chrome users.
Fix & Optimize
Review the specific DOM elements causing issues, implement structural changes, and watch your Google Page Experience signals turn green.
Lab & Field Data Combined
Stop guessing with isolated tests. We aggregate your Lighthouse simulation scores with actual Chrome User Experience Report (CrUX) field data.
Element-Level Debugging
Don't just get a bad score—find the culprit. Our analyzer highlights the exact HTML nodes and images that are causing layout shifts or delaying render times.
Historical Performance Tracking
Keep a pulse on your vitals. Monitor how changes to your CSS, JavaScript, or server affect your LCP, INP, and CLS scores over time.
Trusted by Performance Experts
See how top engineering teams are passing the Page Experience assessment
"This tool identified a layout shift in our footer that three other scanners missed. Our CLS went from 0.4 to 0.05 in one sprint."
"The element-level debugging is a lifesaver. Being able to see exactly which image is causing a high LCP makes optimization twice as fast."
"Integrating this into our pre-deployment workflow saved us from shipping a JS bundle that would have ruined our INP scores."
Why Use Our Vitals Checker?
The most comprehensive performance diagnostic tool for professional SEOs
Deep Scan Technology
We don't just give you a number. We analyze your critical request chain and network waterfalls.
CrUX Data Integration
Overlay your lab results with historical field data from actual Chrome users over the last 28 days.
Element Debugging
Locate the exact DOM nodes causing Cumulative Layout Shifts or slowing down Largest Contentful Paint.
Mobile-First Auditing
Simulate performance on low-end mobile devices and slow 4G networks to optimize for everyone.
Branded PDF Reports
Generate white-label performance audits for your clients with actionable fix recommendations.
Continuous Monitoring
Check your vitals daily and get alerted if a new deployment breaks your page experience score.
Who Needs Core Web Vitals Optimization?
Performance matters for every type of website
E-Commerce Platforms
Every millisecond counts. Improve your LCP to reduce bounce rates and increase checkout conversions.
- Faster product page loads
- Reduced layout shifts
- Higher conversion rates
Publishers & Bloggers
Keep your readers engaged by ensuring your content stays stable and becomes interactive instantly.
- Improved scroll stability
- Instant ad rendering
- Higher dwell time
Agencies & Freelancers
Deliver massive value to your clients by proving your optimizations with branded performance audits.
- Client-ready PDF reports
- Comparative benchmarks
- ROI demonstration
SaaS & Tech Teams
Monitor your web app's responsiveness and interactivity to provide a premium software experience.
- INP monitoring
- JS execution profiling
- Performance regression checks
Core Web Vitals FAQ
Everything you need to know about Google's Page Experience metrics
What is Largest Contentful Paint (LCP)?
LCP measures loading performance. To provide a good user experience, LCP should occur within 2.5 seconds of when the page first starts loading. Common causes of poor LCP include slow server response times, render-blocking JS/CSS, and slow resource load times.
How is Interaction to Next Paint (INP) different from FID?
While First Input Delay (FID) only measured the first interaction, INP measures all interactions on a page. It provides a more comprehensive score of a page's responsiveness. A good INP score is 200 milliseconds or less.
What causes high Cumulative Layout Shift (CLS)?
CLS measures visual stability. It's often caused by images without dimensions, ads/embeds without reserved space, or dynamic content injected from the top. A good CLS score is 0.1 or less.
What is the difference between Lab and Field data?
Lab data is collected in a controlled environment (like Lighthouse), whereas Field data (CrUX) is collected from real users in the real world over time. Field data is what Google actually uses for ranking.
How often should I check my Web Vitals?
You should check your vitals after every major code deployment, design change, or third-party script addition. Regular monitoring helps prevent performance regressions that could hurt your SEO.
Does passing Core Web Vitals guarantee a ranking boost?
While Web Vitals are a confirmed ranking factor, they are one of many. However, passing the Page Experience assessment acts as a "tie-breaker" for similar content and significantly improves user engagement metrics.
Ready to Identify & Fix Your Performance Issues?
Join 25,000+ engineers optimizing their Core Web Vitals today.
