CrUX History Trends

See how your Core Web Vitals have trended over the last ~40 weeks from real Chrome users — LCP, INP, CLS, FCP and TTFB at the p75 Google grades. Powered by the free Google CrUX History API; the trend view the old CrUX Dashboard used to give.

Why watch Core Web Vitals over time, not once

A single lab test tells you how one page loaded on one device right now. It cannot tell you whether a redeploy, a new hero image, a third-party script or a traffic shift to slower devices degraded the experience your real visitors get. Because Google grades the p75 (75th-percentile) field value, a regression can build for weeks before it crosses a threshold and flips your Search Console assessment. Plotting ~40 weeks of history is how you catch that drift while it is still cheap to fix, and how you confirm a performance change actually moved the numbers users feel.

How to read the trend charts

Each metric gets its own sparkline of the p75 value across CrUX’s rolling 28-day windows. Two dashed lines mark Google’s “good” and “poor”thresholds, so where your line sits between them is your grade at a glance. Remember that for Core Web Vitals lower is better — a line trending down is labelled improving, a line trending up is worsening. LCP and FCP read in seconds, INP and TTFB in milliseconds, and CLS is a unitless shift score.

Turning a worsening metric into a fix

LCP creeping up — oversized hero images, slow server response or render-blocking CSS/JS delaying the main content.
INP getting worse — heavy JavaScript on interaction; break up long tasks and trim third-party handlers.
CLS rising — images, ads or embeds without reserved space, or fonts that reflow the page.
TTFB climbing — a server, host or CDN problem, not a front-end one; check caching and origin latency.

Frequently asked questions

What is the Chrome UX Report (CrUX)?

CrUX is Google’s dataset of real-user performance, collected from actual Chrome visitors who opt in. It’s the “field data” Google uses for the Core Web Vitals part of page experience — as opposed to “lab data” from a one-off test like Lighthouse. This tool charts the p75 (75th-percentile) value over time, which is exactly what Google grades.

Which metrics does it show?

LCP (Largest Contentful Paint — loading), INP (Interaction to Next Paint — responsiveness, which replaced FID), CLS (Cumulative Layout Shift — visual stability), plus FCP (First Contentful Paint) and TTFB (Time to First Byte). For each, you get the p75 trend with the “good” and “poor” thresholds marked.

Why does it say there’s no data for my site?

CrUX only publishes data for origins with enough real Chrome traffic to be statistically significant and anonymous. Newer or lower-traffic sites often aren’t covered yet. That isn’t a problem with your site — it just means Google doesn’t have enough field data. Use a lab test (our UI/UX Checker / PageSpeed) in the meantime.

Is this lab data or real-user data?

Real-user (field) data — aggregated from actual visitors over 28-day rolling windows, shown across roughly the last 40 weeks. It reflects real devices and networks, so it can differ from a clean lab test. It’s the data that actually affects your Core Web Vitals assessment in Search Console.

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