⚡ LCP · CLS · INP

Core Web Vitals Checker

Measure LCP, CLS, INP, TBT and FCP with the exact same Google Lighthouse engine as PageSpeed Insights — plus real-user field data and a one-line fix for every failed audit. Free, no login.

How does the Core Web Vitals Checker work?

It calls the Google PageSpeed Insights API directly from your browser — the same Lighthouse engine and the same numbers as pagespeed.web.dev and Hostinger’s speed test. You get lab metrics, real-user CrUX field data where available, and every failed audit sorted worst-first with a plain-language fix. If Google’s shared no-key quota is momentarily exhausted, the tool retries through 5 routes and then automatically runs a built-in static speed audit of the same failure causes, so you always get actionable results — and you can save a free Google API key once (stored only in your browser) for guaranteed full Lighthouse reports.

  1. Enter a URL and pick mobile or desktop — mobile is what Google ranks with.
  2. Wait 20–30 seconds while Lighthouse loads and measures the page.
  3. Read the vitals — green thresholds are Google’s official “good” bands.
  4. Work the failed-audits list top to bottom — each one names exactly what to change.
  5. Re-run after fixing — lab scores update instantly; field data follows in ~28 days.

What are good Core Web Vitals scores?

Google’s official thresholds: LCP under 2.5 seconds, INP under 200 milliseconds and CLS under 0.1 — measured at the 75th percentile of real users. In the lab, also aim for TBT under 200 ms and FCP under 1.8 seconds. The table below shows all three bands for every metric.

MetricGoodNeeds improvementPoor
LCP (Largest Contentful Paint)≤ 2.5 s2.5–4 s> 4 s
INP (Interaction to Next Paint)≤ 200 ms200–500 ms> 500 ms
CLS (Cumulative Layout Shift)≤ 0.10.1–0.25> 0.25
FCP (First Contentful Paint)≤ 1.8 s1.8–3 s> 3 s
TBT (Total Blocking Time)≤ 200 ms200–600 ms> 600 ms

Run a free core web vitals test on any page in about thirty seconds — this is a Google Core Web Vitals checker in the literal sense, because it calls Google's own PageSpeed Insights engine and reports the same LCP, INP and CLS numbers, plus real-user field data. Bookmark it as your core web vitals check online: no login, no quota games, and every failed audit comes with a specific fix.

What a Core Web Vitals check tells you

Searches for a website Core Web Vitals checker all want the same three numbers — LCP (loading), CLS (visual stability) and INP (responsiveness) — because those are the field metrics Google actually uses. This core web vitals checker reports all three for any URL, so you know exactly which one is holding your page back before you start optimizing.

Frequently asked questions

Yes — it calls the same Google Lighthouse API, so the performance score and every metric match pagespeed.web.dev and Hostinger’s speed test exactly. Small run-to-run variance (±3–5 points) is normal for any Lighthouse test.
Lab data is a fresh Lighthouse run on an emulated device — instant and repeatable. Field data (CrUX) is the 75th percentile of real Chrome users over the last 28 days — it’s what actually affects your Google ranking, and it appears only for sites with enough traffic.
Mobile Lighthouse simulates a mid-range phone on a slow 4G connection, so the same page takes longer to load and any main-thread work hurts more. Google ranks with mobile, so optimise for it first.
Follow the failed-audits list in the report — it’s sorted worst-first. Typically render-blocking CSS/fonts (hurts LCP), unreserved space for images or injected content (hurts CLS), and heavy third-party JavaScript (hurts INP/TBT).
CrUX field data is a rolling 28-day window, refreshed daily. After you ship fixes, lab scores improve immediately but field data takes up to a month to fully reflect the change.
Yes, completely free with no login. The check runs from your browser straight to Google’s public API — nothing is stored on our side.
Enter your URL — the checker runs Google Lighthouse plus real-user CrUX data and reports LCP, CLS, INP, TBT and FCP with a one-line fix per failed metric.

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