Lighthouse Score Simulator
Estimate Lighthouse performance score from manual metrics including FCP, LCP, TTI, TBT, CLS, and Speed Index with calculation breakdown
Enter your page metrics to estimate a Lighthouse Performance score (0-100). Weights match Lighthouse v10+.
FCP (First Contentful Paint)
Weight: 10%
seconds
Good: ≤1.8s | Poor: >3.0s
LCP (Largest Contentful Paint)
Weight: 25%
seconds
Good: ≤2.5s | Poor: >4.0s
SI (Speed Index)
Weight: 10%
seconds
Good: ≤3.4s | Poor: >5.8s
TTI (Time to Interactive)
Weight: 10%
seconds
Good: ≤3.8s | Poor: >7.3s
TBT (Total Blocking Time)
Weight: 30%
ms
Good: ≤200ms | Poor: >600ms
CLS (Cumulative Layout Shift)
Weight: 25%
score
Good: ≤0.1 | Poor: >0.25
More Developer Tools tools at toool.cc