Core Web Vitals checker
See whether real visitors pass Google’s Core Web Vitals: Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift, measured at the 75th percentile over 28 days, on mobile and desktop.
Runs Google Lighthouse on mobile and desktop at the same time, plus real-user Chrome data. Takes about 20–40 seconds.
How to read your Core Web Vitals
The verdict at the top is what Google uses: Passed means LCP, INP and CLS are all in the good range for at least 75% of visits. Each bar shows the full spread, so you can see whether you are safely inside the good range or just scraping past the line.
Below it is the lab test: a single load on a simulated device. Lab and field rarely agree exactly, and they don’t need to. Use the field verdict to decide whether you have a problem, and the lab diagnostics (filmstrip, LCP element, opportunities) to find why.
| Metric | Good | Needs improvement | Poor |
|---|---|---|---|
| LCP | ≤ 2.5 s | 2.5–4 s | > 4 s |
| INP | ≤ 200 ms | 200–500 ms | > 500 ms |
| CLS | ≤ 0.1 | 0.1–0.25 | > 0.25 |
Want the background? Read Core Web Vitals explained.
Questions people ask
Where does the Core Web Vitals data come from?
From the Chrome UX Report (CrUX), Google’s public dataset of real-user timings from Chrome users who have opted in to usage statistics. It is the same data Search Console’s Core Web Vitals report and Google’s page experience signals use, over a rolling 28-day window.
Why does it say “origin” instead of my URL?
CrUX only publishes URL-level data for pages with enough traffic. When a page is below that threshold, we show the origin-level numbers (all pages on the domain combined) and label them clearly.
I fixed my site. Why hasn’t the result changed?
Field data is a 28-day rolling window, so a fix shows up gradually and fully after about four weeks. The lab numbers on the same report update immediately, so use them to confirm the fix worked.
Why is there no INP in the lab test?
INP needs real people tapping and typing, which a lab load can’t do. Lighthouse reports Total Blocking Time instead: long JavaScript tasks during load, which are the most common cause of slow interactions.
What does “Passed” require?
All three Core Web Vitals (LCP, INP and CLS) must be “good” at the 75th percentile. If INP has no data, LCP and CLS decide the result.