Lighthouse produces a score from 0 to 100 for each category. The scoring method differs by category.Documentation Index
Fetch the complete documentation index at: https://mintlify.com/GoogleChrome/lighthouse/llms.txt
Use this file to discover all available pages before exploring further.
Score ranges
| Range | Label |
|---|---|
| 0–49 | Fail (red) |
| 50–89 | Needs improvement (orange) |
| 90–100 | Pass (green) |
Scores can vary between runs due to network conditions, CPU load, and other environmental factors — even on the same page. Run Lighthouse multiple times and average the results when doing detailed analysis.
Performance
The Performance score is a weighted average of several speed metrics including First Contentful Paint, Largest Contentful Paint, Total Blocking Time, Cumulative Layout Shift, and Speed Index. The weights of each metric are adjusted periodically to better reflect the user experience. For the full breakdown of metric weights and how each is calculated, see the Lighthouse Performance Scoring guide on developer.chrome.com.Accessibility
The Accessibility score is a weighted average of individual audit results. Each audit is a pass/fail — there are no partial scores. The audit weights for Lighthouse v7 are:| Audit | Weight |
|---|---|
| aria-allowed-attr | 4.1% |
| aria-hidden-body | 4.1% |
| aria-required-attr | 4.1% |
| aria-required-children | 4.1% |
| aria-required-parent | 4.1% |
| aria-roles | 4.1% |
| aria-valid-attr-value | 4.1% |
| aria-valid-attr | 4.1% |
| button-name | 4.1% |
| duplicate-id-aria | 4.1% |
| image-alt | 4.1% |
| input-image-alt | 4.1% |
| label | 4.1% |
| meta-refresh | 4.1% |
| meta-viewport | 4.1% |
| video-caption | 4.1% |
| accesskeys | 1.2% |
| aria-command-name | 1.2% |
| aria-hidden-focus | 1.2% |
| aria-input-field-name | 1.2% |
| aria-meter-name | 1.2% |
| aria-progressbar-name | 1.2% |
| aria-toggle-field-name | 1.2% |
| aria-tooltip-name | 1.2% |
| aria-treeitem-name | 1.2% |
| bypass | 1.2% |
| color-contrast | 1.2% |
| definition-list | 1.2% |
| dlitem | 1.2% |
| document-title | 1.2% |
| duplicate-id-active | 1.2% |
| frame-title | 1.2% |
| html-has-lang | 1.2% |
| html-lang-valid | 1.2% |
| link-name | 1.2% |
| list | 1.2% |
| listitem | 1.2% |
| object-alt | 1.2% |
| tabindex | 1.2% |
| td-headers-attr | 1.2% |
| th-has-data-cells | 1.2% |
| valid-lang | 1.2% |
| form-field-multiple-labels | 0.8% |
| heading-order | 0.8% |
Automated detection covers only a subset of accessibility issues. A high accessibility score does not guarantee a fully accessible site. Manual testing is also recommended.