Test the speed and Core Web Vitals of a page with Google Lighthouse.
The website speed test runs Google Lighthouse through the PageSpeed Insights API and shows the performance, accessibility, best practices and SEO scores of a page, its lab metrics – First Contentful Paint, Largest Contentful Paint, Total Blocking Time, Cumulative Layout Shift and Speed Index – and the list of improvements with the biggest impact.
When Google has enough data, you also see the Core Web Vitals of real Chrome users over the last 28 days, the data Google uses for rankings.
Performance, accessibility, best practices and SEO.
Lab metrics and real-user field data.
The audits with the biggest savings first.
How the page looked when it finished loading.
90 or more is good, 50–89 needs improvement, under 50 is poor. Mobile scores are usually lower than desktop.
Largest Contentful Paint (loading), Interaction to Next Paint (responsiveness) and Cumulative Layout Shift (visual stability).
Network and server conditions vary. Run the test a few times and look at the trend.