Lighthouse performance score

Lighthouse performance score for the page, out of 100. A lab measurement on a simulated mobile connection — a useful comparison, not a report of what your visitors saw.

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The performance score is the headline number of a Lighthouse audit: a weighted blend of lab metrics — First Contentful Paint, Largest Contentful Paint, Total Blocking Time, Cumulative Layout Shift and Speed Index — mapped onto a scale from 0 to 100. It is a quick way to compare two versions of a page, or your page with a competitor's.

How SiteScan measures it

The report asks Google's PageSpeed Insights API to audit the home page twice, once with the mobile profile (a mid-range phone on a throttled connection) and once with the desktop one, and shows both columns side by side. One run takes 15–25 seconds, so the figures arrive after the rest of the report; a result for the same address is reused for six hours.

• Green — 90 or above.
• Amber — 50 to 89.
• Red — below 50.

The score moves a few points between runs, and it is not what Google ranks on: search uses the field data from real Chrome users, described under data source. Treat a low lab score as a pointer to the metrics below it. The usual levers are a lighter, earlier-loading hero image, less render-blocking CSS and JavaScript, fewer third-party scripts, and long cache lifetimes for static files.