Combine Lighthouse category scores into an overall weighted result.
The four categories are averaged equally, but performance is the only one measured from real timings, so it fluctuates between runs while the others are deterministic audits. Accessibility and SEO are largely fixable once, whereas performance requires ongoing attention, which is why the gap between them tends to widen over a project's life.
Lighthouse Score
Overall = mean of the four category scores
Overall = mean of the four category scores The four categories are averaged equally, but performance is the only one measured from real timings, so it fluctuates between runs while the others are deterministic audits.
Accessibility and SEO are largely fixable once, whereas performance requires ongoing attention, which is why the gap between them tends to widen over a project's life.
This calculator takes 4 inputs: Performance score, Accessibility score, Best practices score, SEO score. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.