Core Web Vitals Checker
See whether a page passes Google's Core Web Vitals. The checker pulls real-user data from the Chrome UX Report for the page and the whole site — Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift at the 75th percentile — with the share of good, needs-improvement and poor visits, plus lab diagnostics to fix what fails.
Enter a URL and choose mobile or desktop. The checker queries Google's PageSpeed Insights API for 28-day real-user Chrome data at the page and origin level, shows the Core Web Vitals assessment (passed only if LCP, INP and CLS are all good at the 75th percentile), the distribution of each metric, and Lighthouse lab diagnostics for fixing failures.
Runs Google Lighthouse through the official PageSpeed Insights API and pulls real-user Chrome data (CrUX) when Google has it for the page.
Google-Accurate
Pixel limits & real search data
Instant Results
Full analysis in seconds
No Sign-Up
Free, no credits or email
Suggest a Feature or Improvement for Core Web Vitals Checker
Need custom options, higher limits, or extra format support? Let our engineering team know!
How to use Core Web Vitals Checker
- 1Enter a page URL and choose Mobile or Desktop.
- 2Click Check Core Web Vitals.
- 3Read the assessment and each metric's 75th-percentile value and distribution.
- 4Use the lab metrics and fixes to improve failing metrics; real-user data updates over 28 days.
The three Core Web Vitals
Largest Contentful Paint (LCP) measures loading: the main content should appear within 2.5 seconds. Interaction to Next Paint (INP), which replaced First Input Delay in March 2024, measures responsiveness: the page should react to taps and clicks within 200 ms. Cumulative Layout Shift (CLS) measures visual stability: keep it at 0.1 or less.
Google assesses each at the 75th percentile of real visits over 28 days, separately for mobile and desktop. A page passes when all three are in the good range.
No data? Here's why
The Chrome UX Report only includes pages and sites with enough real Chrome visits. New or low-traffic pages often show no page-level data; the checker then falls back to the whole site's data, and if even that is missing it shows lab results only. Lab metrics can't measure INP, so Total Blocking Time is the closest lab proxy. For a full performance report use the Page Speed Checker.
Frequently Asked Questions
What are good Core Web Vitals scores?
LCP of 2.5 seconds or less, INP of 200 milliseconds or less, and CLS of 0.1 or less, measured at the 75th percentile of page loads.
I fixed my site — why haven't the numbers changed?
Real-user data covers the previous 28 days, so improvements show up gradually over about four weeks. Lab metrics update immediately.
Are Core Web Vitals a ranking factor?
Yes, as part of Google's page experience signals, but relevance and content quality matter much more. Good vitals help most when competing pages are otherwise similar.
Where does the data come from?
From Google's official PageSpeed Insights API: a Lighthouse test run by Google, plus real-user Chrome UX Report data when Google has enough visits for the page. Results are cached for 15 minutes, and each visitor has a daily test limit.
Is this SEO tool free? Do I need to sign up?
It's completely free with no sign-up, no email and no daily credits. Use it as often as you like.
Related Tools
Page Speed Checker
Test any page's speed on mobile and desktop with Google Lighthouse — scores, metrics and what to fix.
Mobile-Friendly Test
Check if a page is mobile-friendly: viewport, zoom, fixed widths, plugins — plus a real phone screenshot.
SEO Checker
Audit any page's SEO — meta tags, headings, content, images, links, schema and technical health.