Core Web Vitals Checker
Measure LCP, CLS and INP — powered by Google PageSpeed Insights. Free, mobile or desktop.
Core Web Vitals are a confirmed Google ranking factor and the clearest proxy for how fast and stable a page feels to real visitors. This checker runs the page through Google PageSpeed Insights and surfaces LCP, CLS and INP — plus supporting metrics — color-coded against Google’s own thresholds so you know exactly what to fix.
Performance is only one part of site health. Run a full website audit to grade SSL, redirects, headers and meta tags in one shot.
How it works
- 01
Enter a URL
Type the page you want to measure — pick mobile or desktop with the toggle.
- 02
Run the check
Sitewell calls Google PageSpeed Insights, which loads the page in Lighthouse and measures its Core Web Vitals.
- 03
Read the metrics
See LCP, CLS, INP, FCP and TTFB color-coded good / needs-improvement / poor, plus an overall performance score.
Frequently asked questions
- What are Core Web Vitals?
- Core Web Vitals are Google's three user-experience metrics: Largest Contentful Paint (LCP) measures loading, Cumulative Layout Shift (CLS) measures visual stability, and Interaction to Next Paint (INP) measures responsiveness. They are a confirmed Google ranking signal, so good scores help both users and SEO.
- What counts as a good score?
- Google's thresholds are LCP under 2.5 seconds, CLS under 0.1, and INP under 200 milliseconds for a 'good' rating. Between those and roughly LCP 4s / CLS 0.25 / INP 500ms is 'needs improvement', and anything beyond is 'poor'.
- Where does this data come from — field or lab?
- This tool runs Google PageSpeed Insights, which returns Lighthouse lab measurements (a controlled, repeatable test). Real-world field data from the Chrome UX Report can differ, since it reflects actual visitors on varied devices and networks.
- Why do mobile and desktop scores differ?
- PageSpeed Insights simulates a slower CPU and network on mobile, which is how most users browse, so mobile scores are usually lower. Toggle the device strategy to see both — and prioritize whichever your audience mostly uses.
Related tools
Website Audit
One-URL health score across SSL, headers, meta and more.
HTTP Status Checker
Check status codes for many URLs at once.
Redirect Checker
Trace 301/302 redirect chains and catch loops.
SSL Checker
Check SSL certificate and domain expiry dates.
Header Checker
Inspect security and SEO response headers.
Meta Tag Checker
Audit titles, descriptions and Open Graph tags.