PageSpeed Matters
    PageSpeed Matters
    Tools & Data Sources · Glossary

    Chrome User Experience Report (CrUX) · Definition & Explanation 2026

    The Chrome User Experience Report (CrUX) is Google's public dataset of real-user performance metrics collected from millions of opted-in Chrome users worldwide. It is the single most important performance data source because it is the field data Google uses for ranking decisions in the Page Experience ranking signal.

    CrUX aggregates Core Web Vitals (LCP, INP, CLS) plus FCP and TTFB at both origin-level (entire domain) and URL-level (individual pages) using a rolling 28-day window. Data is evaluated at the 75th percentile — meaning 75% of real user experiences must meet the 'good' threshold for a metric to pass.

    CrUX data is accessible through multiple surfaces: PageSpeed Insights (field data section), Google Search Console (Core Web Vitals report), BigQuery (full historical dataset), CrUX API (programmatic access), and the CrUX Dashboard (Data Studio visualization).

    In 2026, CrUX covers approximately 15 million origins. Pages or origins without sufficient Chrome traffic lack CrUX data, in which case Google falls back to origin-level assessment for ranking purposes.

    Updated 2026-02-28
    M
    By Matt Suffoletto

    TL;DR — Quick Summary

    CrUX is Google's public dataset of real Chrome user performance data — the field data source Google uses for ranking. It tracks CWV + FCP + TTFB at p75 over a 28-day rolling window. Accessible via PSI, Search Console, BigQuery, and API.

    What is Chrome User Experience Report (CrUX)?

    The Chrome User Experience Report (CrUX) provides real-user experience metrics for millions of websites. Data is aggregated at origin-level and URL-level using a rolling 28-day window. Includes all CWV plus FCP and TTFB. Accessible via PSI, BigQuery, CrUX API, and CrUX Dashboard.

    Key characteristics:

    • •Data source — Opted-in Chrome users (anonymous, aggregated).
    • •Granularity — Origin-level and URL-level.
    • •Window — Rolling 28 days.
    • •Percentile — 75th percentile (p75) for pass/fail.
    • •Metrics — LCP, INP, CLS, FCP, TTFB.
    • •Coverage — ~15 million origins in 2026.

    History & Evolution

    Key milestones:

    • •2017 — CrUX launched as a BigQuery public dataset.
    • •2018 — PSI rebuilt to surface CrUX data alongside Lighthouse.
    • •2020 — Core Web Vitals announced. CrUX becomes the official data source for CWV ranking signals.
    • •2021 — Page Experience Update rolls out. CrUX data directly influences rankings.
    • •2024 — INP replaces FID in CrUX. URL-level data coverage expanded.
    • •2025–2026 — CrUX covers ~15M origins. API v2 with enhanced historical data.

    How CrUX is Measured

    CrUX collects performance metrics from opted-in Chrome users (those who share usage statistics). Data is anonymous, aggregated, and published monthly (BigQuery) and in real-time (API, PSI).

    Access methods:

    • •PageSpeed Insights — 'Discover what your real users are experiencing' section.
    • •Search Console — Core Web Vitals report for all indexed URLs.
    • •BigQuery — Full historical dataset for custom analysis.
    • •CrUX API — Programmatic access for dashboards. Free, rate-limited.
    • •CrUX Dashboard — Pre-built Data Studio visualization.
    • •HTTP Archive — Monthly crawl data including CrUX metrics for trend analysis.

    Key rule: Field data (CrUX) determines Google rankings. Lab data (Lighthouse, WebPageTest) is for debugging and iteration.

    Common Causes of Poor CrUX Scores

    Common CrUX data issues:

    1. 1No URL-level data — Page lacks sufficient Chrome traffic. CrUX needs meaningful pageviews over 28 days.
    2. 2Origin-level failing but URL-level passing — A few slow pages drag down the entire domain.
    3. 3Field data worse than lab data — Real users on budget devices/slow networks experience worse performance.
    4. 4Data not updating after fixes — CrUX uses a 28-day rolling window. Full improvement takes 28 days.
    5. 5Mobile vs desktop divergence — Mobile CrUX often fails while desktop passes.

    Frequently Asked Questions

    For step-by-step optimization, platform-specific fixes, code examples, and case studies, read our full guide:

    The Ultimate Guide to Website Performance Measurement, Tools & Data: Lab, Field & Everything Between in 2026
    The Ultimate Guide to Core Web Vitals: How to Pass All Metrics & Boost Rankings in 2026

    Struggling with CrUX?

    Request a free speed audit and we'll identify exactly what's holding your scores back.