Why Does Testing Matter More Than Reading About Accessibility?
The WCAG guidelines tell you what to aim for. Only testing tells you what is actually broken on your own site. WebAIM's 2025 survey of the top million homepages found detectable failures on about 95% of them. Automated tools catch somewhere between 30% and 57% of issues, so the rest needs checking by hand.
If you followed last week's WCAG 2.2 quick wins guide, you already know what the standard asks for. Knowing it and meeting it are different jobs, and the gap between them is where most small businesses get stuck.
You can read every accessibility guide going and still have a site that shuts out disabled visitors. The only way to find out is to test it and then fix what turns up.
This guide covers which tools to use, how to test by hand, what to fix first, and how to make accessibility part of your normal routine so it doesn't become a once-a-year panic.
What Are the Best Free Accessibility Testing Tools?
The three best free tools are WAVE (visual overlay, great for beginners), axe DevTools (zero false positives, developer-friendly), and Google Lighthouse (built into Chrome, combines accessibility with performance and SEO).
WAVE: best for learning
WAVE, made by WebAIM, is the most beginner-friendly accessibility scanner. Install the Chrome or Firefox extension, visit any page on your site, and click the WAVE icon. It overlays coloured icons directly on your page showing exactly where problems are.
- Green tick = passed check
- Red error = serious problem
- Yellow alert = needs human judgement
- Blue feature = structural element detected
The catch is that WAVE checks one page at a time. For a whole site you either visit every page in turn or pay for the WAVE API or a service such as Pope Tech that scans the lot.
axe DevTools: best for accuracy
axe DevTools, built by Deque, runs inside Chrome or Edge DevTools. Open DevTools (F12), find the axe tab, and click "Scan." It reports issues with the exact HTML line, the WCAG criterion affected, and a fix suggestion.
Its main selling point is that it is designed to report no false positives. If axe flags something, it is a real problem. WAVE and Lighthouse sometimes flag things that need a human to judge; axe leaves those out of its automatic results.
- The free version covers individual use with unlimited scans.
- Pro costs roughly £45 per user per month and adds guided tests and build-pipeline checks.
- The engine underneath, axe-core, is open source and is also what Lighthouse uses.
Google Lighthouse: best for a quick baseline
Lighthouse is built into Chrome DevTools. Open DevTools, go to the Lighthouse tab, tick "Accessibility" and generate a report. It scores your page out of 100 and lists issues with affected elements.
Lighthouse runs only a subset of the axe-core rules, so it finds less than running axe directly. A score of 100 does not mean the page is accessible. Treat it as a starting point.
Free Accessibility Tools Compared
| Feature | WAVE | axe DevTools | Lighthouse | Pa11y |
|---|---|---|---|---|
| Developer | WebAIM | Deque | Open source | |
| Type | Browser extension | Ext. + CLI | Chrome DevTools | CLI tool |
| WCAG 2.2 | Yes | Yes | Partial | Yes |
| Visual overlay | Best-in-class | DevTools panel | None | None |
| CI/CD | Paid only | Yes | Yes | Yes (free) |
| Price | Free | Free / £45 Pro | Free | Free |
We'd run all three. WAVE shows you the problems on the page itself, axe gives a precise list a developer can work through, and Lighthouse gives you a quick number to track.
Which Specialist Tools Are Worth Knowing About?
Beyond the big three, Pa11y (free CLI tool) is excellent for automated testing in CI/CD pipelines. Accessibility Insights (Microsoft) provides guided manual testing workflows.
Pa11y: free and built for automation
Pa11y is a command-line tool that runs axe-core or HTML_CodeSniffer against your pages. Install with npm install -g pa11y, then run pa11y https://yoursite.co.uk for an instant report.
Where it really helps is pa11y-ci. Add it to a GitHub Actions or GitLab CI pipeline and it will stop a release that introduces new accessibility errors.
Accessibility Insights (Microsoft)
Accessibility Insights is a free browser extension that provides a guided manual testing workflow. It walks you through keyboard testing, tab order verification, and visual checks step by step.
How Do You Manually Test for Accessibility Issues?
Automated tools catch 30–57% of WCAG issues. The rest requires manual testing. A manual pass on a small business site (5–15 pages) takes 2–4 hours.
Step 1: Keyboard-Only Navigation
Put the mouse to one side and use the Tab key to move through every page.
- Can you reach every interactive element?
- Is the focus indicator visible at all times?
- Can you open/close dropdown menus with Enter/Space and Escape?
- Does the tab order follow the visual layout?
Step 2: Screen Reader Spot-Check
- On Windows, use NVDA (free from nvaccess.org).
- On a Mac or iPhone, VoiceOver is built in (Cmd+F5 on a Mac).
- On Android, turn on TalkBack under Settings, then Accessibility.
Step 3: 200% Zoom Test
Press Ctrl/Cmd + "+" until the page is at 200% zoom. Check that no text overlaps, the layout holds, and all content remains accessible without horizontal scrolling.
Step 4: Mobile Tap Targets
WCAG 2.2 introduced criterion 2.5.8: all clickable targets must be at least 24×24 CSS pixels. On your phone, try tapping every link, button, and form field.
Step 5: Colour and Contrast Manual Review
Automated tools miss text over images, hover state contrast, placeholder text, and error message contrast. Use the WebAIM Contrast Checker. Target is 4.5:1 for normal text and 3:1 for large text.
How Do You Prioritise What to Fix First?
Start with serious problems that are quick to fix. Missing alt text, poor contrast and empty links take minutes each. Then plan the bigger jobs, such as keyboard traps and forms that can't be completed without a mouse.
| Priority | Impact | Examples | Action |
|---|---|---|---|
| Fix immediately | Critical/High | Missing alt text, low contrast, empty links | This week |
| Plan this sprint | Critical/High | Keyboard traps, inaccessible forms | 1–2 weeks |
| Weekly maintenance | Medium/Low | Link text improvements, heading fixes | Regular workflow |
| Next release | Medium/Low | Custom components, CMS templates | Next dev cycle |
What Does Remediation Cost in the UK?
| Service | Typical UK Price | What You Get |
|---|---|---|
| Quick-win sprint | £1,500–£4,000 | Fix most common issues |
| Professional audit | £600–£5,000+ | Manual + automated testing |
| Full remediation | £2,500–£6,000+ | Fix and verify compliance |
Need professional help?
Our accessibility audit and our full website audit both start at £14.99.
How Do You Build Accessibility Into Your Workflow?
Accessibility isn't a one-off project. Run automated scans monthly, test by hand every quarter and get a professional audit once a year. And skip the overlay widgets.
A word on overlay widgets
- In 2025 the US Federal Trade Commission ordered accessiBe to pay $1 million over misleading claims about what its widget could do.
- About a quarter of US digital accessibility lawsuits filed in 2024 were against sites that already had an overlay installed.
- Many disabled users actively dislike overlays, which add another layer to fight with and leave the underlying code unchanged.
- Fixing the HTML and CSS is the only approach that actually works.
Does Improving Accessibility Actually Help SEO?
Yes, because much of the groundwork is the same. One industry study of sites that improved their accessibility reported 23% more organic traffic and rankings for 27% more keywords.
| Accessibility Practice | SEO Benefit |
|---|---|
| Descriptive alt text | Image search visibility |
| Semantic heading structure | Better crawlability |
| Descriptive link text | Stronger internal linking |
| Clean, valid HTML | Faster page speed |
Your Free Weekend Accessibility Sprint
You can make meaningful accessibility progress in a single weekend. Saturday morning: run WAVE and Lighthouse. Saturday afternoon: fix structure. Sunday: manual testing.
Saturday Morning (2–3 hours)
- Install WAVE and axe DevTools browser extensions
- Run WAVE on your top 5 pages
- Fix every contrast error and missing alt text
- Run Lighthouse on the same pages
Saturday Afternoon (2–3 hours)
- Fix every form label issue
- Replace "Click here" with descriptive text
- Check the headings, with one H1 per page
- Add lang="en" to your html tag
Sunday (2–3 hours)
- Unplug mouse, Tab through entire site
- Install NVDA or VoiceOver, spot-check
- Zoom to 200%, check layout
- Publish an accessibility statement
Resources
- WebAIM Contrast Checker, for testing colour pairs
- WAVE browser extension, a visual page scanner
- axe DevTools, for developer testing
- NVDA, a free Windows screen reader
- WCAG 2.2 Quick Reference
- Daedalus AI Accessibility Check, our free automated scan
Frequently Asked Questions
What free tools can I use to test my website accessibility?
WAVE, axe DevTools and Google Lighthouse are all free and cover most needs between them. If you want automated checks from the command line, Pa11y is free and open source.
Do I need a professional accessibility audit or can I do it myself?
On a site of under 15 pages you can do a useful first audit yourself. A professional audit of a small site usually costs £600 to £1,200, and because it includes manual testing it finds far more than the 30–57% automated tools manage.
What are accessibility overlay widgets and should I use one?
They add a script to your site that claims to fix accessibility problems, but the underlying code stays broken. The US FTC made accessiBe pay $1 million over its claims, and many disabled users find the widgets get in the way. Fix the HTML and CSS instead.
How often should I test my website for accessibility?
Run automated scans on your highest-traffic pages monthly. Perform manual keyboard and screen reader testing quarterly. Conduct a full professional audit annually.
Does improving accessibility help my SEO rankings?
Very likely. Clear headings, alt text and descriptive links help search engines as much as people, and one industry study reported 23% more organic traffic for sites that improved their accessibility.
How long does it take to fix accessibility issues?
The most common issues can be fixed in 4–8 hours over a weekend. A full accessibility sprint typically takes 2–4 weeks of part-time effort.
Want a second pair of eyes?
Previous part: WCAG 2.2 quick wins for UK small businesses. For the legal side, see WCAG 2.2 and the European Accessibility Act.
This guide is for informational purposes and does not constitute legal advice. For specific compliance questions, consult a qualified solicitor specialising in digital accessibility law.