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Core Web Vitals checker

Lab Lighthouse and field Chrome UX Report data from Google PageSpeed Insights.

Answers: core web vitals checker · pagespeed insights alternative · lcp cls inp test

Read the step-by-step guide · Blog workflow

What this does not measure

  • A lab run is synthetic. It measures one load of one URL on Google's hardware, and your visitors are not on that hardware.
  • Field data is a 28-day rolling summary and may be absent entirely for a low-traffic URL. When it is missing the tool says so rather than showing a zero.
  • Neither number is a ranking factor on its own. Core Web Vitals are a tiebreaker, not a score for the page.

Lab tests typically take 20–40 seconds. Field metrics come from Chrome UX Report when enough real-user data exists.