Track field performance over time
Chart up to forty weeks of p75 Core Web Vitals from the Chrome UX Report for an origin or URL.
Free, no signup. Lab tests tell you how a page performs on your machine; Chrome's real users tell you how it performs on theirs. Chart 40 weeks of that field data — the same numbers Google uses for ranking — for up to 5 sites side by side.
Checks run from our server; we fetch the URL you enter and don't keep the results. Results are cached at the edge until the next weekly refresh. Research counters record run totals only; they store no URL, domain, IP, user agent, hash, or pseudonymous identifier. Anonymous run-level outcome counters may be used for aggregate research; URLs, domains, IPs, and identifiers are never included, and no statistic is released below 100 runs.
Sample data. The CrUX API key isn't configured on this deployment — these charts are generated placeholders so you can see how the tool works.
The one-year view uses 12 monthly points. Lifetime defaults to yearly aggregation and can switch to monthly detail.
Source: Chrome UX Report BigQuery monthly origin dataset. Monthly origin-level BigQuery observations remain separate from the recent weekly History API series. Annual values average available monthly p75 observations and do not bridge missing months.
Data: Chrome UX Report History API — weekly p75 values over 28-day rolling collection periods, updated every Monday. A site only appears when enough Chrome users visit it.
Free, no signup. "Who's actually fastest" is a different question for every Core Web Vital. Rank a field of sites on real-Chrome-user data — a separate board for LCP, INP, CLS, FCP, TTFB, and the overall pass. Pick a curated group or paste your own origins.
Checks run from our server; we fetch the URL you enter and don't keep the results. Results are cached at the edge until the next weekly refresh. Anonymous run-level outcome counters may be used for aggregate research; URLs, domains, IPs, and identifiers are never included, and no statistic is released below 100 runs.
Sample data. The CrUX API key isn't configured on this deployment — these boards are generated placeholders so you can see how the leaderboard works.
Add one origin on mobile:
example.com (origin — most CrUX data)
competitor.com (add up to 5)
device: mobile …and the scorecard returns:
Illustrative example — real CrUX field data requires a live API lookup this static page can't make; the pass verdict bucketing shown matches this tool's actual good/needs-improvement/poor thresholds
example.com has the most CrUX data; you can also add a specific URL. Repeat to
stack up to 5 targets for a side-by-side race.Checking a single page's field data right now? Use the Core Web Vitals Checker. Want the numbers explained? Read the Core Web Vitals guide.
Each metric tile is coloured by its p75 value against the official Core Web Vitals thresholds:
The card verdict rolls those three up:
FCP and TTFB show below the core three as supporting diagnostics (they are not part of the Core Web Vitals pass). Each core tile also carries a 40-week delta so you can see direction, and the trend charts shade the good, needs-improvement, and poor bands behind every line.
The tool calls the Google Chrome UX Report History API through a cached edge proxy. That API returns up to 40 weekly data points per metric, each the p75 across a 28-day rolling collection window, refreshed every Monday. All the charting, bucketing, and pass verdict math runs client-side in your browser from that raw response; results are cached at the edge until the next weekly refresh, so re-running a popular comparison is instant and spends no API quota.
The number for each metric is the p75 — the value 75% of real Chrome visits were at or below — which is the exact figure Google evaluates. A site only appears when it has enough Chrome traffic to form a stable sample; targets below that bar are reported as no CrUX data rather than guessed.
This is field data, not a lab audit. It tells you what real users experienced, not which element or script caused it — for that, run a lab tool on the page. Sites without enough Chrome traffic return no data and cannot be charted, and deep URLs often have less coverage than their origin. The values reflect a trailing 28-day window and refresh weekly, so a fix you shipped this morning will not show up for days. And because CrUX is Chrome-only, traffic from other browsers is not represented.
CrUXChrome User Experience Report — Google's public dataset of real-world (field) performance data from eligible Chrome users. It's the official field-data source behind the Core Web Vitals program. is the Chrome UX Report — real Core Web VitalsGoogle's three real-user UX metrics — LCP (loading), INP (responsiveness), and CLS (visual stability) — used by Google's ranking systems, with no official weight attached, measured on field data. measurements collected from actual Chrome users who opted in to sharing usage statistics. It is field data: what people really experienced on your pages. A LighthouseLighthouse is Google's free, open-source tool that audits a page under simulated lab conditions and scores it 0–100 across Performance, Accessibility, Best Practices, and SEO. It's lab data — useful for debugging, not a ranking signal. or PageSpeed lab score is a single simulated load on one throttled device, useful for debugging but not what Google uses for ranking. Google ranks on the field (CrUX) data, which is exactly what this tool charts.
A metric is "good" if its 75th-percentile value stays at or below the good threshold: LCP 2.5 seconds, INP 200 milliseconds, and CLS 0.10. It is "poor" above the poor threshold: LCP 4 seconds, INP 500 milliseconds, and CLS 0.25. Anything between the two is "needs improvement." A site passes Core Web Vitals only when all three of LCP, INP, and CLS are in the good range.
CrUX only reports a URL or origin once it has enough real Chrome traffic to form a stable sample. New pages, low-traffic sites, and specific deep URLs often fall below that bar. Bare origins (your root domain) collect far more visits than any single page, so if a deep URL returns nothing, try the origin instead — it usually has data even when individual pages do not.
CrUX reports the 75th percentile of each metric — the value that 75% of visits were at or below. It is deliberately stricter than an average: it means three out of four of your real visits were at least this fast, so a fast median cannot hide a slow tail. Google uses this same p75 value to decide whether each metric is good, needs improvement, or poor.
The History API returns weekly data points, each a 28-day rolling collection window, refreshed every Monday. This tool charts up to 40 of those weekly periods — roughly the trailing year — so you can see whether a fix actually moved the field data and when a regression began, rather than just today's snapshot.
Saved targets, named lists, and recent check summaries remain only in this browser.
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Where this tool helps
Chart up to forty weeks of p75 Core Web Vitals from the Chrome UX Report for an origin or URL.
Place up to five comparable origins or URLs on one chart to understand relative field performance.
Look for sustained changes in LCP, INP, CLS, FCP, or TTFB around a known deployment date.
Export the observed series or send a shareable view while noting when CrUX lacks enough eligible traffic.
Watch the full workflow
A lab test shows one simulated visit. CrUX shows what real Chrome users experienced. I’ll explain when this tracker helps, how to build a comparison, how to read the sample result and thresholds, its charts, leaderboard, exports, limitations, and the next diagnostic step.
This tracker charts Chrome U-X Report field data: anonymized measurements from eligible real Chrome visits. It can compare as many as five origins or U-R-Ls over forty weekly periods. Use it to monitor user experience and competitors, not to debug a single simulated page load.
Use the tool after a performance release, during a regression investigation, for monthly reporting, to compare mobile and desktop, or to benchmark a competitor set. History helps answer whether a change persisted and roughly when it began. A bare origin usually has more coverage than a deep page.
Enter a bare domain or full U-R-L and select Add. Repeat for up to five targets. Choose mobile or desktop and either p-seventy-five values or visit distributions, then select Compare. Origins are the safest starting point because individual pages need enough traffic to qualify separately.
The clearly labeled illustrative card shows L-C-P at two-point-three seconds and C-L-S at zero-point-zero-six, both good, while I-N-P at two-hundred-forty milliseconds needs improvement. Because all three core metrics must be good together, the origin is not passing Core Web Vitals.
The arrows compare the long trend, not just this week. In the example, loading and layout shift improve while interaction latency worsens. That points the next investigation toward interaction-heavy pages. Treat the dates, direction, and metric band together instead of reducing the report to one pass label.
Good p-seventy-five thresholds are L-C-P at most two-point-five seconds, I-N-P at most two hundred milliseconds, and C-L-S at most zero-point-one. Values between good and poor need improvement. Poor begins above four seconds, five hundred milliseconds, and zero-point-two-five respectively.
Each weekly point represents a rolling twenty-eight-day collection window, refreshed on Monday. The charts shade good, needs-improvement, and poor bands and can include L-C-P, I-N-P, C-L-S, F-C-P, and T-T-F-B. Expect gradual movement after a fix because old visits age out over time.
Switch to Leaderboard to rank a curated group, or paste up to twenty-five origins of your own. Select one metric, overall Core Web Vitals pass, and a device. This is useful for directional benchmarking, but different audiences, page mixes, devices, and traffic volumes limit one-to-one conclusions.
Main features include five-target comparisons, forty weeks of history, p-seventy-five and distribution views, mobile and desktop data, threshold-colored scorecards and charts, leaderboard mode, share links, C-S-V export, and private baseline export and import. Supporting F-C-P and T-T-F-B do not affect the Core Web Vitals verdict.
No CrUX data is not a failing score. It means the selected origin or page and device lacks a stable eligible sample for one or more metrics. Try the origin, confirm the form factor, or use your own analytics and lab measurements. The tool does not invent values when coverage is missing.
CrUX tells you what eligible Chrome users experienced, not which element, request, or script caused it. Data is Chrome-only, coverage favors higher-traffic targets, and the rolling window delays visible changes. Competitor differences may reflect audiences and page mix, so use rankings as context rather than proof of implementation quality.
Export or baseline the exact targets, form factor, dates, p-seventy-five values, and coverage notes. Choose the weakest metric, locate the change window, and test representative page templates with PageSpeed Insights, Lighthouse, the Core Web Vitals Checker, and your own telemetry. After fixing the cause, monitor several weekly windows before declaring success.
Use the scorecard to identify the weak metric and the history to find when it changed. Then test representative pages with lab and field tools, investigate the responsible templates or scripts, ship a focused fix, and watch later rolling windows for a durable improvement.