Lighthouse Performance Calculator

Adjust the core metrics and see how Lighthouse builds the performance score.

Weights: FCP 10%, SI 10%, LCP 25%, TBT 30%, CLS 25%

0
FCP (First Contentful Paint)
Weight 10% • Good ≤ 1.8s
1,800 ms 100
SI (Speed Index)
Weight 10% • Good ≤ 3.4s
3,400 ms 100
LCP (Largest Contentful Paint)
Weight 25% • Good ≤ 2.5s
2,500 ms 100
TBT (Total Blocking Time)
Weight 30% • Good ≤ 200ms
200 ms 100
CLS (Cumulative Layout Shift)
Weight 25% • Good ≤ 0.1
0.10 100

Based on Chrome Lighthouse performance-scoring. View official docs.