- Free tools like WAVE, axe, and Lighthouse test only 30–40% of WCAG criteria.
- A passing automated scan does NOT mean your site is ADA compliant.
- Keyboard navigation, screen reader flows, and cognitive accessibility require manual human testing.
- Use free tools as a starting point — then get a professional manual audit for legal-grade compliance.
Best Free ADA Website Scanning Tools
These are the three most reliable free accessibility scanning tools. We recommend running all three on your site for the most complete automated picture:
| Tool | Provider | Strengths | Limitations |
|---|---|---|---|
| axe DevTools Browser Extension | Deque Systems | Most accurate automated engine, developer-friendly output, zero false positives policy | Tests only current page state, cannot test keyboard flows or screen reader |
| WAVE Web Tool + Extension | WebAIM | Visual overlay shows errors in page context, contrast checker, structural outline view | Higher false positive rate than axe, no dynamic content testing |
| Lighthouse Chrome DevTools | Built into Chrome, scores 0–100, integrates with CI/CD pipelines | Uses axe-core subset, limited rule set compared to full axe DevTools |
How to Run a Free Accessibility Scan
- Install axe DevTools: Add the axe DevTools browser extension to Chrome or Firefox. Open your website, press F12, go to the "axe DevTools" tab, and click "Scan All of My Page."
- Run WAVE: Visit wave.webaim.org, enter your URL, and review the visual overlay of errors, alerts, and structural elements.
- Check Lighthouse: In Chrome, press F12 → Lighthouse tab → check "Accessibility" → click "Analyze page." Aim for 90+ but remember this is not comprehensive.
What Free Scans Cannot Detect (60–70% of Issues)
According to research by Deque Systems, automated tools can reliably detect only 30–40% of WCAG 2.2 Level AA success criteria. Here's what they miss:
- Keyboard navigation: Can you navigate every interactive element using Tab, Enter, and arrow keys? Do focus indicators appear? Can you escape modals?
- Screen reader compatibility: Does content make sense when read linearly? Are dynamic updates announced? Do form errors provide clear instructions?
- Cognitive accessibility: Are instructions clear? Do error messages explain what went wrong and how to fix it? Are timeout warnings provided?
- Dynamic content: Do carousels, modals, accordions, tabs, and infinite scroll work with assistive technology?
- Focus management: After opening a modal, does focus move into it? After closing, does it return to the trigger element?
- Meaningful sequence: Does the visual order match the DOM order? Do CSS changes affect reading sequence?
- Alternative text quality: Automated tools can detect missing alt text — but cannot evaluate whether existing alt text is accurate, descriptive, or meaningful.
🔍 Automated Tools Find
- Missing alt text on images
- Insufficient color contrast ratios
- Missing form labels
- Missing document language
- Duplicate IDs
- Empty links / buttons
🧑💻 Manual Audit Finds
- Keyboard navigation failures
- Screen reader incompatibilities
- Focus management issues
- Cognitive accessibility gaps
- Dynamic content ARIA failures
- Meaningful alt text accuracy
When to Get a Professional Manual Audit
A free scan is a useful first step. Get a professional WCAG 2.2 manual audit when:
- Your business serves the public (ADA Title III applies to you)
- You operate in a high-risk industry (e-commerce, healthcare, restaurants, law firms)
- You've received an ADA demand letter
- You need legal-grade compliance documentation (VPAT, compliance certificate)
- You're a California business facing Unruh Act exposure
- Your free scan shows issues — there are almost certainly more that weren't detected
View pricing details or check if you qualify for the IRS Disabled Access Credit ($5,000/year back).
Frequently Asked Questions
No. Free automated scans detect only 30–40% of WCAG violations (Deque Systems). They cannot test keyboard navigation, screen reader compatibility, cognitive accessibility, or dynamic content. A passing scan does NOT mean your site is ADA compliant — it means only the automatically-detectable issues were checked.
The best free tools are: (1) axe DevTools by Deque — most accurate automated engine, (2) WAVE by WebAIM — visual overlay showing issues in context, (3) Google Lighthouse accessibility audit — built into Chrome DevTools. Use all three together for the most complete automated picture.
No. Zero automated errors means your site passed the 30–40% of WCAG criteria that can be automatically tested. The remaining 60–70% — including keyboard navigation, screen reader flows, cognitive accessibility, and complex interaction patterns — require manual human testing. Sites with zero automated errors frequently have 20+ manual violations.
A complyTech WCAG 2.2 manual audit starts at $495 for micro-sites (1–10 pages) and ranges to $3,500–$7,500 for e-commerce. Includes manual expert review, VPAT, remediation roadmap, and compliance certificate. Most businesses qualify for the IRS Disabled Access Credit — up to $5,000/year back.