CrUX Report

The Chrome User Experience Report is Google's public dataset of real-user performance metrics from opted-in Chrome browsers. It powers field data in PSI and Search Console.

Definition

CrUX collects anonymized performance data from millions of Chrome users who opted in to usage statistics. The dataset includes LCP, INP, CLS, FCP, and TTFB, segmented by device type and connection type. Metrics are reported at the 75th percentile (p75).

How CrUX Works

Chrome records performance metrics and sends them to Google. These are aggregated by origin and URL into histograms. Data is available via the CrUX API, BigQuery, PSI, and Search Console.

Common Misunderstandings

CrUX is NOT real-time. It uses a 28-day rolling window. A fix deployed today takes up to 28 days to reflect. CrUX only includes opted-in Chrome users, biasing toward Android Chrome. Despite limitations, it is the authoritative dataset for CWV evaluation.

Accessing CrUX

CrUX API accepts URL/origin queries and returns histograms. BigQuery provides the full raw dataset. Search Console surfaces CrUX data in template-based views.

Note

Requires ~1,000 visits per URL for data availability. Data is segmented by country and connection type in BigQuery.

In code

curl -X POST 'https://chromeuxreport.googleapis.com/v1/records:queryRecord?key=KEY' -H 'Content-Type: application/json' -d '{"url":"https://example.com","metrics":["largest_contentful_paint"]}'

Common questions

Q: How long until optimizations show in CrUX?

A: Up to 28 days due to the rolling window.

Q: Does CrUX include all browsers?

A: No. Only opted-in Chrome users.

Key takeaways:

• Google's official field data source.

• 28-day rolling window.

• Reported at p75.

• Requires ~1,000 visits per URL.