Documentation
Core Web Vitals: real-user LCP, INP and CLS, week by week
Weekly 75th-percentile LCP, INP and CLS from the Chrome UX Report History API for your whole site or one page, rated against Google's thresholds.
The Core Web Vitals report (titled Core Web Vitals History) shows how real Chrome users experience your site, week by week. It reads the Chrome UX Report History API, the same field data that feeds Search Console's Core Web Vitals report, and rates each metric at the 75th percentile against Google's thresholds. Use it to see whether a release made your pages faster or slower, long before a lab test would tell you how visitors felt it.
Run the report
- Scope: Whole site queries the origin (for example
https://www.example.com), which aggregates every page Chrome users visited. Single page queries one URL. - Origin or Page URL: prefilled with your property's origin; edit it to check another host or page.
- Device: All devices, Phone, Desktop or Tablet. With All devices, the report also loads each device separately and adds a Summary by device table.
- Press Run report.
Results are cached for a day, since the data only changes weekly. The report queries the API with a CrUX API key; AutoPSEO provides one, so there is nothing to set up. The API Key button links to Google's instructions if you want a key for your own tools.
What you see
The verdict line says whether the scope Passes Core Web Vitals: every core metric with data is rated Good. Five cards follow, one per metric, each with the latest 75th-percentile value, its rating, the change against four weeks earlier and the share of page loads rated good.
| Metric | Measures | Good | Poor |
|---|---|---|---|
| LCP, Largest Contentful Paint | Loading: when the largest visible element is rendered | 2.5 s or less | over 4 s |
| INP, Interaction to Next Paint | Responsiveness: delay after clicks, taps and key presses | 200 ms or less | over 500 ms |
| CLS, Cumulative Layout Shift | Visual stability: how much content moves while loading | 0.1 or less | over 0.25 |
| FCP, First Contentful Paint | When the first text or image appears | 1.8 s or less | over 3 s |
| TTFB, Time to First Byte | How quickly the server starts responding | 0.8 s or less | over 1.8 s |
LCP, INP and CLS are the Core Web Vitals; FCP and TTFB are supporting metrics that help explain a poor LCP. Values between the two limits need improvement. Google assesses each metric at the 75th percentile of page loads, separately for mobile and desktop (web.dev: Web Vitals). INP replaced First Input Delay as a Core Web Vital on 12 March 2024.
A trend counts as improving or worsening when the latest value moved at least 5% from four weeks earlier. Charts plot each metric's weekly 75th percentile with its good, needs-improvement and poor shares, and the table lists every week with all five values and the share of good LCP experiences.
How to read the history
Each point is a weekly collection period that summarises the previous 28 days of visits, so a fix shows up gradually over about four weeks rather than overnight. The API returns 25 weekly periods by default, roughly the last six months (CrUX History API).
- A step change that lines up with a deploy, a new tag manager script or a theme update is the usual pattern; mark the date with an annotation.
- Phone worse than desktop is common, since phones have less processing power and often slower connections. Weigh it by how much of your search traffic comes from mobile.
- Origin good, page poor: the origin blends every page together, so check your heaviest templates one by one.
When there is no data
Chrome only publishes a record for a public origin or URL with enough real Chrome visits; otherwise the report says Not enough field data (CrUX methodology). New or low-traffic pages often have no URL-level record even when the origin has one. The CrUX APIs also have no country breakdown, so the numbers cover all your visitors worldwide.
How AutoPSEO helps
Articles AutoPSEO delivers are rendered by your own site, so they inherit your templates' performance. If AutoPSEO hosts a section for you, the hosted renderer serves the article pages itself; run the report on one of those URLs to check them. For a fuller explanation of the three metrics, see what LCP, INP and CLS mean and how to fix poor Core Web Vitals.