Web Accessibility
What Is a Website Accessibility Audit?
A plain English explanation of what an accessibility audit checks, how it runs, what you get at the end, and how it differs from a quick scan.
· 6 min read
AI-narrated audio version of this article. The page scrolls along while it plays; scroll yourself anytime to take over.
The short answer
An accessibility audit is a structured checkup of your website against the Web Content Accessibility Guidelines, known as WCAG. An auditor, helped by automated tools, works through your pages and writes down every place where a visitor using a screen reader (software that reads page content aloud and lets a person navigate by keyboard), a keyboard, or another assistive technology (any tool that helps people with disabilities use the web, like screen readers or voice control) would get stuck.
The W3C Web Accessibility Initiative publishes WCAG, and its WCAG overview presents the standard as the shared reference that governments, businesses, and developers use to define what accessible means in practice.
Think of it like a home inspection. The inspector does not sell you the house or fix the roof. The inspector tells you, in writing, what is broken, how serious it is, and what to do about it. An audit does the same for your website.
It also covers the templates and third party pieces your pages use, because visitors experience it all as one site, and so does the law.
Why businesses run one
Three reasons, and only one of them is legal.
First, customers. The web is supposed to work for everyone who visits it. The W3C Web Accessibility Initiative makes the point plainly in its introduction to web accessibility: the web is fundamentally designed to work for all people, whatever their hardware, software, language, location, or ability. When your site breaks that promise, real customers are locked out, and they rarely tell you. They just leave.
Second, the law. In 2024, the Justice Department published a final rule requiring state and local government websites and mobile apps to meet WCAG 2.1 AA, and ADA.gov explains that rule in plain language. Private businesses watch the same yardstick, because courts and complaints point to it too.
Third, self interest. Every barrier an audit finds is a place where a paying customer gave up. Fixing barriers is not charity work. It is recovering sales you were already earning the traffic for.
What an audit actually checks
WCAG is built on four ideas: content should be perceivable, operable, understandable, and robust. In practice, an audit checks things like these:
- Color contrast. Can visitors with low vision read your text against its background?
- Text alternatives. Does every meaningful image carry a description a screen reader can speak?
- Keyboard access. Can someone reach and use every link, button, and form without a mouse?
- Forms and errors. Is every field labeled, and does each error message say what went wrong and how to fix it?
- Headings and structure. Does the page outline make sense when it is read aloud from top to bottom?
- Video and audio. Do your videos have captions, and does your audio content have a transcript?
A thorough audit samples your key page types: the home page, product or service pages, checkout and contact forms, and anything a customer must complete to buy from you.
How an audit runs, step by step
Most audits follow the same four moves, in this order.
One, scope. You and the auditor agree on the pages to examine and the standard to test against, usually WCAG 2.2 AA (the current target level most policies aim for, where AA is the mid level of strictness) for new work. Getting this in writing matters, because an audit of five pages and an audit of fifty are very different products.
Two, automated scanning. Software sweeps the chosen pages and flags mechanical failures: missing labels, weak contrast, broken code. It is the fastest, cheapest way to clear the obvious problems before human time gets spent.
Three, manual testing. A person tabs through the site using only a keyboard, listens to key pages through a screen reader, and zooms the layout to 200 percent. This is where the serious barriers surface, because software cannot judge meaning, order, or clarity.
Four, the report. Every finding lists where it lives, who it blocks, how severe it is, and how to fix it.
What you get at the end
You should walk away with three things. A findings list you can hand to any developer, ranked by how much each problem hurts real users rather than by how easy it is to fix. A plain language summary that an owner can read without a technical background. And a retest after the fixes ship, confirming that each barrier is actually gone and not just marked closed.
Some audits also produce a formal conformance report that records how your site scored against each WCAG criterion. (A formal pass or fail checklist against each WCAG success criterion.) Government buyers often ask for that document by name. Even when nobody asks, it is written proof that the work was done properly, by a person, against a named standard.
An audit is not a scan, and not a widget
Three products get confused constantly, and the confusion is expensive.
A scan is the automated step alone: fast, useful, and partial. It has never experienced your site the way a person would.
A widget or overlay is a small tool pasted on top of your site that promises instant compliance. It does not repair your underlying code, it does not test anything, and it is not an audit of any kind.
An audit is the full process: tools, human testing, and a written record. If a vendor cannot tell you who tested your site, with which assistive technology, and against which version of WCAG, what you bought was a scan wearing a nicer name.
How often to run one
Run a full audit before a redesign launches, after any major change to your templates, checkout, or forms, and at least once a year if your site changes often. Run the automated scan far more frequently, because new pages and small edits quietly reintroduce old problems.
At Thanos Labs, this is the work our Web Accessibility AI agent supports day to day: it watches for barriers, drafts the fixes, and a human reviews and approves every change before it reaches your visitors. The audit is how you learn the truth about your site. What matters is what you do with it.