Overview
The Lighthouse Performance score is a single number (0 to 100) that summarizes the overall performance of a web page. It is calculated based on a weighted mix of metrics including LCP, TBT, CLS, Speed Index, and FCP.
Scoring Tiers
- 0 to 49 (Red): Poor performance.
- 50 to 89 (Orange): Needs improvement.
- 90 to 100 (Green): Good performance.
Evolution
Google periodically updates the weighting of the metrics in the Lighthouse score to better reflect modern user experience priorities and browser capabilities.