Skip to content

How the Lighthouse performance score works

Speed1 min readFixes check lighthouse-performance-score

The score is a weighted mix of five lab metrics measured in a throttled Chrome. It is not what your visitors see, but it is the fastest way to find what slows them down.

Step by step, with screenshots: A monthly site health routine, done in 30 minutes →

Check your own site

Runs this check and the other 186, free, in about 45 seconds.

What a passing site looks like

  • Lighthouse performance score: passesinfo onlyeffort M

Lighthouse performance score

Why it matters. This is the number Google's own tools show for your page. It combines five of the lab metrics below (all except TTFB), weighted the way Lighthouse weights them. 90 and above is green.

How to fix it.
  1. Work through the failed metrics and opportunities below in order of points; the score follows.

Filed under Speed & Core Web Vitals. Copy is generated from the same catalogue that scores every report, so what you read here is what the report says.