Chrome UX Report (CrUX)

Chrome UX Report (CrUX) is a public dataset of real-world performance data collected from Chrome users as they browse the web. It records how fast and stable pages actually are for visitors, and it is the source of the field data Google uses to assess Core Web Vitals.

Written by Paul Hoda, SEO consultant since 2005. Last updated 8 November 2026.

Where the data comes from

CrUX collects data from Chrome users who have opted in to share usage statistics and sync their browsing history. It records metrics such as Largest Contentful Paint, Interaction to Next Paint, Cumulative Layout Shift, First Contentful Paint and Time to First Byte, along with device type and connection type.

Only pages and origins with enough traffic are included. Smaller sites may have origin-level data (the whole domain) but no data for individual URLs, and some sites have no CrUX data at all.

Why CrUX matters for SEO

When Google assesses Core Web Vitals as part of its page experience signals, it uses real-user field data of this kind rather than lab tests. The figures are based on the 75th percentile of visits over a rolling 28-day window, so a page passes only if most visitors have a good experience.

This means a fast result on your own computer is not enough. If real visitors on slower phones and networks struggle, CrUX will show it.

How to access CrUX data

  • PageSpeed Insights: the quickest way to see CrUX data for a single URL or origin.
  • Google Search Console: the Core Web Vitals report groups similar URLs and flags those that are poor or need improvement.
  • CrUX API and History API: let developers pull current and historical data into their own tools.
  • CrUX Vis: a Google tool for charting how an origin or URL has changed over time.
  • BigQuery: a monthly dataset covering millions of origins, useful for large-scale analysis and competitor comparisons.

How to use it in practice

  1. Check whether your site has origin-level and URL-level data.
  2. Identify which metric is failing and on which device type.
  3. Use lab tools such as Lighthouse to diagnose the cause.
  4. Ship fixes, then watch CrUX over the following four weeks to confirm the improvement.
  5. Compare your origin with competitors to see how your user experience stacks up.

Limitations

  • It only covers Chrome users who meet the opt-in criteria, not Safari or Firefox visitors.
  • The 28-day window means changes appear slowly.
  • Low-traffic pages are often missing, so you may need your own real-user monitoring for detail.
  • It shows what is happening, not why. You still need lab tools and developer investigation to find the cause of a poor score.

Despite these limits, CrUX is the closest view you have of how Google judges real-world page experience on your site.

Key Takeaways

  • CrUX is a public dataset of real Chrome users’ experience of web pages.
  • It is the source of the field data behind Google’s Core Web Vitals assessment.
  • Results use the 75th percentile over a rolling 28-day window.
  • Low-traffic pages may have no URL-level data, only origin-level data.
  • You can view it in PageSpeed Insights, Search Console, the CrUX API and BigQuery.

Related Terms

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