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Free Core Web Vitals & PageSpeed Checker
Run a measured mobile or desktop performance test using PageSpeed and Lighthouse data. Review performance scores, lab metrics, real-user Core Web Vitals when available, diagnostics and practical optimization opportunities.
Measured PageSpeed data, not estimated scores
SEO Mentor runs a PageSpeed measurement for the URL and reports the returned Lighthouse performance, accessibility, best-practices and SEO scores. Lab metrics and optimization opportunities come from the measured test rather than HTML-count estimates.
Lab data and real-user data are different
Lighthouse lab metrics are generated during the current test. Real-user Core Web Vitals, when available for the page or origin, represent aggregated user experience. Some URLs do not have enough eligible field data, so SEO Mentor clearly marks field data as unavailable instead of inventing values.
Use performance evidence with a wider SEO review
Page speed is one part of technical SEO. Review performance findings together with crawlability, indexability, content quality, search intent and internal structure before prioritising changes.
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Frequently Asked Questions
Does SEO Mentor calculate a Google PageSpeed score?
No. It does not invent Lighthouse or Core Web Vitals scores. The tool reviews observable performance-related signals and provides a route to Google PageSpeed Insights when measured Google data is needed.
What is the difference between lab and field performance data?
Lab tests measure a controlled run, while field data reflects experiences collected from real users when sufficient data exists. Both can be useful but answer different performance questions.
Can performance affect SEO and users?
Slow or unstable pages can harm user experience, and page experience signals can matter in search. Performance should still be improved for users rather than chasing a single score.
What is the difference between lab and field data?
Lab data is generated in a controlled Lighthouse test, while field data represents aggregated real-user experiences when sufficient data is available. They answer different diagnostic questions and may not match.
Why can PageSpeed scores change between runs?
Network conditions, server response, third-party scripts and test variability can change lab measurements. Look for persistent patterns rather than treating a single run as an exact permanent score.
Continue Your SEO Workflow
Compare website appearance and performance using Website Screenshot Generator, Website Traffic Checker, Global Website Speed & Ping Test and Website Browser by Country. Each check covers a different aspect of your website, so compare the evidence before making changes.
