Core Web Vitals Reference

Good / needs improvement / poor thresholds for LCP, INP, CLS, FCP, TTFB.

Google's Core Web Vitals field thresholds, as published in the official documentation. 75th-percentile real-user measurements should fall in the "Good" column.

MetricAcronymGoodNeeds improvementPoor
Largest Contentful Paint
Largest element rendered above the fold.
LCP ≤ 2.5s 2.5s – 4s > 4s
Interaction to Next Paint
Worst observed interaction → next paint latency.
INP ≤ 200ms 200ms – 500ms > 500ms
Cumulative Layout Shift
Sum of unexpected layout shifts.
CLS ≤ 0.1 0.1 – 0.25 > 0.25
First Contentful Paint
First text/image rendered.
FCP ≤ 1.8s 1.8s – 3s > 3s
Time to First Byte
Network/server latency before any byte returns.
TTFB ≤ 800ms 800ms – 1.8s > 1.8s
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