What Is CrUX (Chrome UX Report)?

Purpose

Explain what the Chrome User Experience Report (CrUX) is and how it is used to evaluate real world page experience.

What CrUX is

CrUX is a public dataset from Google that reports real user experience metrics for eligible websites. It is based on aggregated data from real Chrome users.

Google reference:

CrUX overview https://developer.chrome.com/docs/crux/

What CrUX reports

CrUX includes Core Web Vitals and related signals, such as:

Largest Contentful Paint (LCP)
Cumulative Layout Shift (CLS)
Interaction to Next Paint (INP)

Google reference:

Core Web Vitals https://web.dev/vitals/

Key concepts

It is percentile based

CrUX is typically discussed using percentiles, such as p75, which is aligned with how Google evaluates Core Web Vitals.

It is aggregated

CrUX is not a per session debug tool. It is designed for high level trends.

It has eligibility limits

Not every site and page path appears in CrUX. Smaller traffic sites may not have enough data.

How to use CrUX in measurement

CrUX is useful for:

Tracking external, Google aligned experience trends
Comparing device and geography segments when available
Validating that improvements are visible at a population level

What Is RUM (Real User Monitoring)?
CrUX vs RUM: When to Use Each
Understanding Regional / Device Differences in CrUX