What a WCAG 2.1 AA website accessibility audit actually checks
Quick answer: A WCAG 2.1 AA audit checks whether people with disabilities can perceive, operate and understand your website, and whether it works with assistive technology. It tests things like image alt text, color contrast, keyboard navigation, form labels and heading structure against the W3C’s Web Content Accessibility Guidelines.
What is WCAG 2.1 AA?
WCAG stands for Web Content Accessibility Guidelines. They’re published by the W3C, the group that sets web standards. Version 2.1 has three levels: A, AA and AAA. Level AA is the practical target for most business websites. The U.S. Department of Justice’s web accessibility guidance points to WCAG as a helpful standard.
What are the four principles an audit tests?
WCAG groups its rules under four principles, often shortened to POUR:
| Principle | The question it asks | Example check |
|---|---|---|
| Perceivable | Can everyone perceive the content? | Images have alt text; text has enough contrast |
| Operable | Can everyone use the controls? | Everything works with a keyboard |
| Understandable | Is it clear and predictable? | Forms explain errors in plain words |
| Robust | Does it work with assistive technology? | Code is valid and labeled for screen readers |
Which failures show up most on small-business sites?
The same few problems appear again and again:
- Missing alt text on photos, logos and buttons made of images.
- Low color contrast, especially light gray text and text over photos.
- Unlabeled form fields, so a screen reader can’t say what to type.
- Skipped heading levels, which break the outline screen reader users navigate by.
- Link text like “click here”, which means nothing out of context.
- Menus and pop-ups that trap keyboard users.
Most of these are fixed in an afternoon, not a rebuild.
What can’t an automated audit catch?
An automated scan is a fast first pass. It can’t judge meaning. It can tell you an image has alt text, but not whether “IMG_2041.jpg” describes it. It can’t tell whether a video’s captions are accurate, or whether error messages make sense. A good audit pairs the scan with a person’s review of the key pages.
Why should a small business care?
A site that some visitors can’t use loses customers. Screen reader users, people with low vision, and anyone who uses a keyboard instead of a mouse are all trying to buy from you. Accessibility work also tends to make a site cleaner and easier for everyone.
Want to see where your site stands? Start with our free SEO and accessibility audit.
How to check your own site in 10 minutes
- Unplug the mouse
Use only the Tab, Shift+Tab and Enter keys. Can you reach every link, menu and form field, and can you see where you are?
- Zoom to 200 percent
Zoom your browser to 200 percent. Does text still fit, or does content overlap and disappear?
- Check the images
Right-click a few images and inspect them. Do meaningful images have alt text that describes them?
- Try the contact form
Click each field’s label. Does the cursor jump into the field? If not, the label isn’t connected.
- Run an automated scan
Use a free automated audit to catch contrast, missing labels and structure problems you can’t see by eye.
Sources and further reading
Common questions
Can an automated tool find every accessibility problem?
No. Automated tools catch many common failures, such as missing alt text, low contrast and unlabeled form fields. Judgment calls need a person. A tool can see that alt text exists, but not whether it describes the image usefully. Keyboard-only navigation also needs a human test. A good audit uses both.
What's the difference between WCAG levels A, AA and AAA?
Level A covers the most basic barriers, like images with no text alternative. Level AA adds important ones like color contrast and consistent navigation, and it’s the level most organizations aim for. Level AAA is the strictest. The W3C itself notes it isn’t practical to require AAA for an entire site.
Does accessibility help SEO?
Often, yes. Alt text, clear headings, descriptive link text and fast, well-structured pages help search engines understand a site, just as they help people. Accessible sites also tend to be easier to use on phones. Accessibility isn’t a ranking shortcut, but most fixes improve both at once, so the work rarely goes to waste.