Free Website Accessibility Checker

What this checker tests

Lighthouse's accessibility audit runs around 40 automated checks covering the most common WCAG (Web Content Accessibility Guidelines) violations:

• Color contrast — text vs background ratio (minimum 4.5:1 for normal text)
• Alt text on every meaningful image
• Form labels correctly associated with inputs
• Button and link names that are descriptive (not "click here")
• Semantic HTML — using <button> instead of clickable <div>s
• Tab order and keyboard navigation
• ARIA attributes used correctly (or not abused)
• Heading hierarchy — no skipped levels
• Document language set with lang attribute
• alt="" on decorative images so screen readers skip them

How the score is calculated

Unlike Performance and SEO, the accessibility score is not a weighted average. Any failed audit drops the score significantly. A single contrast failure can take you from 100 to 88.

That's a feature, not a bug — accessibility issues compound. A site with twelve small issues is dramatically less usable than a site with zero.

The most common fixes

1. Color contrast (estimated impact: huge)

Use a tool like the WebAIM contrast checker to test every text/background pair. Aim for 4.5:1 for body text and 3:1 for large text and UI components.

2. Image alt text

Every <img> needs an alt attribute:

• Meaningful image? Describe what it shows in context.
• Decorative image? Use alt="" so screen readers skip it.
• Image in a link? The alt text becomes the link text — make it descriptive of the destination.

3. Form labels

Every <input> needs a label. The most reliable pattern:

<label for="email">Email address</label>
<input id="email" name="email" type="email" />

4. Semantic HTML

Replace clickable divs with real <button> elements. They get keyboard focus, screen reader announcements, and ARIA semantics for free.

5. Skip-to-content link

Add a hidden <a href="#main">Skip to main content</a> at the top of the page so keyboard users can bypass navigation.

What automated tools can't catch

Even a perfect 100 score doesn't guarantee accessibility. Manual testing is still needed for:

• Whether your alt text is meaningful, not just present
• Whether your form error messages are helpful to a screen reader user
• Whether modal dialogs trap focus correctly
• Whether your site is usable with the keyboard alone
• Whether announcements (toasts, errors) are reachable by assistive tech

Run the checker below for an instant baseline, then layer manual testing on top.