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Core Web Vitals Assessor
Classify entered LCP, INP and CLS values against published threshold bands.
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TOOL CORE-WEB-VIT
What this tool does
About the core web vitals assessor
Enter measurements from your own field or lab report to see good, needs-improvement and poor bands. This calculator does not measure a page itself.
Method
- LCP
good <= 2.5s; poor > 4.0s- INP
good <= 200ms; poor > 500ms- CLS
good <= 0.1; poor > 0.25
- Thresholds are evaluated per entered value.
- Use current official documentation when standards change.
How to use it
- Take LCP, INP and CLS values from your field data, PageSpeed report or lab run.
- Enter each measurement.
- Read the band for each metric against the displayed thresholds.
- Prioritise whichever metric sits in “poor” — one red metric fails the whole assessment.
Useful for
- Translate raw LCP/INP/CLS numbers from any report into the good/needs-improvement/poor bands.
- Sanity-check an agency’s performance claims against the published thresholds.
- Track a page across releases by classifying each release’s measurements consistently.
Straight answers
Core Web Vitals Assessor FAQ
What are the Core Web Vitals thresholds?
Good means LCP ≤ 2.5s, INP ≤ 200ms and CLS ≤ 0.1, measured at the 75th percentile of real visits. Poor starts at 4s, 500ms and 0.25. The calculator applies exactly these published bands.
Lab numbers or field numbers — which count?
Field (CrUX) data is what Google actually uses. Lab runs are for diagnosis and vary run to run. Classify both, but fix against field.