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Lighthouse accessibility scoring

The Lighthouse Accessibility score is a weighted average of all accessibility audits. Weighting is based on axe user impact assessments.

Each accessibility audit is pass or fail. Unlike the Performance audits, a page doesn't get points for partially passing an accessibility audit. For example, if some buttons on a page have accessible names, but others don't, the page gets a 0 for the Buttons do not have an accessible name audit.

The following table shows the weighting for each accessibility audit. More heavily weighted audits have a bigger effect on your score. Manual audits aren't included in the table because they don't affect your score.

Audit Weight
[accesskey] values are not unique 3
The page does not contain a heading, skip link, or landmark region 3
[id] attributes on active, focusable elements are not unique 10
Headings skip levels 3
Some elements have a [tabindex] value greater than 0 3
[aria-*] attributes do not match their roles 10
[aria-hidden="true"] is present on the document <body> 10
[aria-hidden="true"] elements contain focusable descendants 10
Not all ARIA input fields have accessible names 10
[role]s do not have all required [aria-*] attributes 10
Elements with an ARIA [role] that require children to contain a specific [role] are missing some or all of those required children 10
[role]s are not contained by their required parent element 10
[role] values are not valid 10
Not all ARIA toggle fields have accessible names 10
[aria-*] attributes do not have valid values 10
[aria-*] attributes are not valid or misspelled 10
ARIA IDs are not all unique 10
Buttons do not have an accessible name 10
Document doesn't have a <title> element 3
Form fields have multiple labels 3
<frame> or <iframe> elements do not have a title 3
Image elements do not have [alt] attributes 10
<input type="image"> elements do not have [alt] text 10
Form elements do not have associated labels 10
Links do not have a discernible name 3
<object> elements do not have [alt] text 3
Background and foreground colors do not have a sufficient contrast ratio 3
<dl>s do not contain only properly ordered <dt> and <dd> groups, <script>, or <template> elements 3
Definition list items are not wrapped in <dl> elements 3
Lists do not contain only <li> elements and script supporting elements (<script> and <template>) 3
List items (<li>) are not contained within <ul> or <ol> parent elements 3
Presentational <table> elements do not avoid using <th>, <caption>, or the [summary] attribute 3
Cells in a <table> element that use the [headers] attribute refer to an element id not found within the same table 3
<th> elements and elements with [role="columnheader"/"rowheader"] do not have data cells they describe 3
The document uses <meta http-equiv="refresh"> 10
[user-scalable="no"] is used in the <meta name="viewport"> element or the [maximum-scale] attribute is less than 5 10
<audio> elements are missing a <track> element with [kind="captions"] 10
<video> elements do not contain a <track> element with [kind="captions"] 10
<video> elements do not contain a <track> element with [kind="description"] 10
<html> element does not have a [lang] attribute 3
<html> element does not have a valid value for its [lang] attribute 3
[lang] attributes do not have a valid value 3
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