CrUX — Chrome User Experience Report
CrUX (Chrome User Experience Report) is Google’s dataset of real user performance metrics collected from Chrome browsers on public URLs. It’s the data source Google uses for the Core Web Vitals ranking signal — which makes it the most authoritative measure of page performance you can access.
What CrUX provides
Section titled “What CrUX provides”CrUX reports field measurements at the 75th percentile — meaning 75% of real users experienced that value or better. Google uses the 75th percentile to account for real-world variability without being skewed by outliers.
Metrics reported:
| Metric | Good | Needs improvement | Poor |
|---|---|---|---|
| LCP | < 2.5s | 2.5s–4s | > 4s |
| INP | < 200ms | 200ms–500ms | > 500ms |
| CLS | < 0.1 | 0.1–0.25 | > 0.25 |
| FCP | < 1.8s | 1.8s–3s | > 3s |
| TTFB | < 800ms | 800ms–1.8s | > 1.8s |
CrUX reports both mobile and desktop scores separately. Google primarily uses mobile for ranking.
Origin vs URL-level data
Section titled “Origin vs URL-level data”CrUX data is available at two granularities:
Origin-level — aggregated across all pages on your domain. This is always available for domains with sufficient traffic. Useful for understanding your overall performance tier.
URL-level — for individual pages with enough traffic for Google to have collected statistically significant data. Not all pages have URL-level data; low-traffic pages fall back to origin-level.
VisibilityIQ shows URL-level data when available and falls back to origin-level with a note. Pages with neither (typically new pages or very low-traffic pages) show “No CrUX data” and display only Lighthouse lab data.
Setting up the connector
Section titled “Setting up the connector”CrUX data is publicly available — you don’t need OAuth credentials. Go to Project → Connectors → CrUX and click Enable. VisibilityIQ will begin fetching CrUX data for your origin and for all crawled URLs on the next sync.
How it appears in audit findings
Section titled “How it appears in audit findings”When CrUX data is connected, performance findings show both field and lab data side by side:
- Field (CrUX) — real users, 75th percentile, mobile and desktop
- Lab (Lighthouse) — synthetic, simulated mid-range Android device on 4G
If field and lab scores disagree significantly (e.g., lab shows “Good” but field shows “Poor”), VisibilityIQ flags this as a finding. The most common causes are:
- Third-party scripts that load differently in real browsers vs Lighthouse’s isolated environment
- Geographic distribution of your users (CrUX reflects actual locations; Lighthouse uses a fixed connection speed)
- Caching — returning users may have cached assets that make field scores better than lab
CrUX in the Performance tab
Section titled “CrUX in the Performance tab”Go to Project → Performance to see a site-wide view of CWV scores across all URLs, segmented by mobile/desktop, with pass/fail status against Google’s thresholds. URLs in the “Poor” band are prioritized in the issue list because they have the most potential ranking uplift from improvement.
Data freshness
Section titled “Data freshness”CrUX data is collected on a 28-day rolling window. This means a performance fix won’t show up in CrUX data immediately — it typically takes 28 days for the old data to age out. VisibilityIQ shows the CrUX data collection date so you can understand how fresh the measurements are.