Good: LCP < 2.5s, INP < 200ms, CLS < 0.1. Needs improvement: LCP 2.5–4s, INP 200–500ms, CLS 0.1–0.25. Poor: above those values.

This tool uses Google PageSpeed Insights API, combining Lighthouse lab data and Chrome UX Report field data when available.

Question 1

What are Core Web Vitals?

Accepted Answer

Core Web Vitals are Google’s key page experience metrics: LCP (loading), INP (interactivity), and CLS (visual stability).

Question 2

What are the thresholds?

Accepted Answer

Good: LCP < 2.5s, INP < 200ms, CLS < 0.1. Needs improvement: LCP 2.5–4s, INP 200–500ms, CLS 0.1–0.25. Poor: above those values.

Question 3

Where does the data come from?

Accepted Answer

This tool uses Google PageSpeed Insights API, combining Lighthouse lab data and Chrome UX Report field data when available.

Core Web Vitals Checker

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