Search for accessibility testing tools and you get pages of them, many with similar names and a “free scan” button. Some are genuinely useful. Some are sales funnels for a widget. And even the good ones each do one narrow job.
So instead of a ranked list, this post sorts the free tools by the job they do: scanning pages, checking color contrast, reading a page aloud like a screen reader, and inspecting the code. For each kind, you will see what it is good at and, just as important, what it will never tell you.
Why one tool is never enough
A home inspector carries several instruments for a reason. A moisture meter finds damp. It does not tell you the stairs are too steep. Accessibility tools are the same. A scanner reads the code and applies rules. A contrast checker measures two colors. A screen reader shows you what a blind visitor hears. None of them sees the whole house.
Automated tools catch only part of the barriers WCAG describes. Many criteria need a person to judge: whether alt text actually describes the image, whether the focus order makes sense, whether an error message helps. That is why a working toolkit mixes machine checks with human ones. Our full accessibility testing method shows where each tool fits in the order of work.
Free accessibility testing tools, sorted by job
Here is the short version. The sections after it explain each row.
| Job | Free examples | Good at | Blind spot |
|---|---|---|---|
| Page scanners | WAVE, axe DevTools (free extension), Lighthouse | Missing alt attributes, empty links and buttons, missing form labels, many contrast failures | Quality of text, keyboard behavior, anything that needs judgment |
| Contrast checkers | Browser-based and desktop contrast analyzers | Exact ratios for any two colors, including ones a scanner cannot read | Only checks the colors you pick |
| Screen readers | NVDA (Windows), VoiceOver (Mac, iPhone), TalkBack (Android) | What a page really sounds like, reading order, names of controls, announcements | Takes practice; one screen reader can hide problems another shows |
| Browser developer tools | Accessibility panes in Chrome, Edge and Firefox | The accessible name and role the browser computes for an element | Shows one element at a time; you have to know what to look for |
| Your own keyboard and browser settings | Tab key, zoom, text spacing bookmarklets | Focus, keyboard traps, reflow, clipped text | Needs you to try every task, by hand |
Page scanners: fast, useful, and easy to over-trust
A scanner loads a page, reads its code and flags patterns that break rules. The three most people meet first are WAVE from WebAIM, the free axe DevTools browser extension from Deque, and the Lighthouse audit built into Chrome.
They differ mostly in how they show results. WAVE draws icons right on the page, which is easy for non-developers to follow. axe lists issues in the browser’s developer tools with the exact element and a link to the rule. Lighthouse gives a single score along with a list of failed audits. If you want walkthroughs, there are separate guides on how to use WAVE on a page, the free axe DevTools extension, and what a Lighthouse accessibility score measures.
What scanners are good at:
- Images with no alt attribute at all.
- Links and buttons with no text, like icon-only social links.
- Form fields with no associated label.
- Many text contrast failures where the colors are set in CSS.
- Missing page language, empty headings, skipped heading levels.
- Some ARIA mistakes, such as an attribute pointing at an ID that does not exist.
What they miss is the bigger list. A scanner cannot tell that alt=”image1″ is meaningless, that a “Submit” button actually deletes something, or that a dropdown menu cannot be opened without a mouse. It cannot judge captions. It usually cannot measure contrast for text over a photo. It only checks the state of the page in front of it, so a popup that never opened was never tested.
Two habits help. Run more than one scanner on important pages, because their rules differ slightly. And be wary of any “free compliance checker” site that turns a scan into a percentage or a badge. A scan result is a to-do list, not a verdict.
Contrast checkers: for the colors scanners cannot read
Under WCAG 1.4.3, body-size text needs 4.5:1 against its background and large text needs 3:1. 1.4.11 asks for 3:1 for icons, field borders and focus indicators against what is next to them. Scanners check text colors set in CSS, but they struggle with text over images, gradients, videos and anything with transparency.
A contrast checker solves that. You give it two colors, usually by typing hex codes or using an eyedropper, and it gives you the ratio and a pass or fail for each level. Desktop analyzers with an eyedropper are especially handy, because you can sample the actual pixels behind hero text or a button on a photo.
Their blind spot is obvious once you say it: they check only the two colors you chose. Sample the lightest part of the photo behind the text, not the darkest, or you will pass something that fails for real visitors.
Screen readers: the only way to hear what users hear
A screen reader turns the page into speech or braille. Testing with one is the single best way to find out whether your buttons have names, your headings make sense and your form errors get announced.
Three free ones cover the main platforms:
- NVDA on Windows, free to download. Pair it with Chrome or Firefox. See our NVDA testing guide for the first few commands.
- VoiceOver, built into every Mac, iPhone and iPad.
- TalkBack, built into Android phones.
JAWS is also widely used on Windows, but it is a paid product. If your audience includes many JAWS users, as some government and workplace audiences do, it can be worth testing there too.
The blind spot here is you. Screen reader testing has a learning curve, and an unfamiliar tester can mistake their own confusion for a site bug, or miss a real one. Practice on a well-built site first so you know what “normal” sounds like.
Browser developer tools: checking the name and role
Chrome, Edge and Firefox each have an accessibility view inside their developer tools. Right-click an element, choose Inspect, and look for the accessibility pane or tab. It shows what the browser tells assistive technology about that element: its role (button, link, heading), its accessible name, and states such as expanded or checked.
This is where you answer the developer’s question, “Why does the screen reader say ‘button’ with no name?” The pane shows whether the name is coming from text, an aria-label, or nowhere. Firefox’s accessibility inspector can also show the whole accessibility tree for a page.
The blind spot is scale. You inspect one element at a time, and you need to know roughly what a correct result looks like. It is a diagnosis tool, best used after a scanner or screen reader has pointed you at a problem.
The tools you already have: a keyboard and the zoom setting
Some of the most valuable checks need no download. Leave the mouse alone and work through the whole site with Tab, Shift+Tab, Enter, Space, the arrow keys and Escape. You are checking that focus is always visible, that it moves in a sensible order, and that nothing traps you. The step-by-step keyboard test covers it in detail.
Then zoom the browser up to 200 percent and further. Text should grow without overlapping, and at narrow widths the page should reflow into one column instead of scrolling sideways. A text spacing bookmarklet, which increases line and letter spacing, quickly shows buttons and boxes that clip their text.
No scanner can do any of this for you, because it is about how the page behaves when a person uses it.
A small free toolkit to start with
If you are an office manager or marketing lead who wants to check your own site, you do not need ten tools. Start with these:
- One scanner you find easy to read. WAVE is friendly for non-developers; axe suits people comfortable in developer tools.
- A contrast checker with an eyedropper, for text over images and brand colors.
- Your keyboard, used on every form and menu.
- NVDA if you are on Windows, VoiceOver if you are on a Mac.
- A spreadsheet to record what you find, page by page.
Use them in roughly that order on your home page, a typical inner page and every form. You will learn more in an afternoon than any single score can tell you.
Frequently asked questions
What is the best free accessibility testing tool?
There is no single best one, because each tool does a different job. For scanning, WAVE is easiest for non-developers and the free axe DevTools extension suits people who use browser developer tools. You still need a contrast checker, a screen reader such as NVDA or VoiceOver, and a keyboard test to cover what scanners cannot judge.
Are free accessibility testing tools accurate?
The reputable ones are accurate about what they check, though they sometimes flag things that turn out fine on review. The bigger issue is coverage. Automated tools catch only part of the barriers WCAG describes, so a clean result does not mean a page is accessible. Treat findings as a starting list and confirm them by hand.
Do I need to pay for accessibility testing software?
Not to get started. Free scanners, contrast checkers, NVDA, VoiceOver and browser developer tools cover a great deal. Paid tools mainly add scanning across many pages, scheduled monitoring, guided tests and reporting. They help teams working at scale, but they do not replace a person testing with a keyboard and a screen reader.
Do these tools work on Shopify, Squarespace or Wix sites?
Yes. Scanners, contrast checkers, screen readers and browser developer tools all test the page a visitor receives, so the platform behind it makes no difference to testing. What changes is the fix. On hosted platforms some markup comes from the theme or the platform itself, so a few issues may only be fixable by switching themes or asking the vendor.
Tools tell you where to look. If you would like an experienced tester to run the human passes and explain the findings, see our manual and screen reader testing, or read more about our ADA website accessibility help as a whole.
Next in this series: WAVE Accessibility Checker: How to Read Your Results
