Chrome User Experience Report.

The Chrome User Experience Report (CrUX) is a public dataset maintained by Google that contains real-world performance metrics collected from opted-in Chrome users across millions of websites. It provides field data — actual measurements from real users on real devices and connections — as opposed to lab data from controlled test environments. CrUX is the data source Google uses to assess Core Web Vitals for ranking purposes.

CrUX vs Lab Data

Lab tools like Lighthouse and PageSpeed Insights can be run on demand in a controlled environment, producing consistent, reproducible scores. But lab scores don't always match real-world user experience — a page may score well in Lighthouse but perform poorly for users on mobile networks in emerging markets. CrUX captures this real-world variation. Google uses the 75th percentile CrUX score (the experience of the slowest-performing quartile of real users) for Core Web Vitals assessment.

Accessing CrUX Data

CrUX data is surfaced in Google Search Console's Core Web Vitals report (showing field data for your site), PageSpeed Insights (which combines lab and field data), and as a raw public dataset in Google BigQuery. Third-party tools like crux.run, Treo, and HTTPArchive provide CrUX dashboards. Sites with insufficient traffic may not have CrUX data — in this case, PageSpeed Insights falls back to lab data only.