A vendor’s email says your site “fails the ADA.” The audit report attached to it lists WCAG success criteria with numbers like 1.4.3 and 2.4.7. Your web designer says they built the site “to WCAG,” and your insurer’s questionnaire asks whether you are ADA compliant. Are those the same thing? Which one are you supposed to meet?
The short version of ADA vs WCAG: one is a US civil rights law, the other is an international technical standard, and in practice the second has become the way people measure the first on websites. This post explains how the two connect, what the levels mean in a sentence each, and which version a US business should aim for. Nothing here is legal advice.
One is a law, the other is a technical standard
The Americans with Disabilities Act is a federal civil rights law, and it predates the web. It prohibits discrimination against people with disabilities across many parts of public life, including government services and businesses open to the public. It says what must not happen to people. It does not say what color your buttons should be or how a dropdown menu should behave, because nobody drafting it was thinking about business websites.
WCAG, the Web Content Accessibility Guidelines, is published by the W3C through its Web Accessibility Initiative. It is not a law in any country by itself. It is a set of testable statements about web content: images have text alternatives, everything works with a keyboard, text has enough contrast, form errors are described in words. Each statement is called a success criterion and has a number.
So the difference between ADA and WCAG comes down to this: the ADA supplies the duty, in general terms, and WCAG supplies a detailed, checkable description of what an accessible page looks like. Neither one replaces the other.
How the two connect in practice
The link between them is not written into the ADA itself. It comes from how government bodies, courts, lawyers and auditors have used WCAG over time.
- Businesses open to the public (Title III). The Justice Department’s long-held position is that the ADA reaches what these businesses publish online, and the web guidance it issued in March 2022 says so again. What DOJ has never done is write a Title III regulation with technical requirements for business sites. WCAG fills the gap: the AA level, in version 2.1 or 2.2, is what most demand letters, settlements and audits measure against.
- State and local governments (Title II). Here the connection is written down. In April 2024 DOJ published a final rule adopting WCAG 2.1 Level AA for the web content and mobile apps of state and local governments. The deadlines vary with the population a government serves and could be revised, so look them up on ADA.gov rather than relying on a blog post.
- Federal agencies (Section 508). This is a different law, the Rehabilitation Act. When the Section 508 standards were refreshed in 2017, WCAG 2.0 AA was folded in by reference. Federal contractors and grantees often meet it through contract terms.
Judges have read Title III differently where websites are concerned, which is one reason the law feels vague to owners. The technical side is much less vague. Whatever the legal argument, the person testing your site will almost always reach for WCAG.
ADA vs WCAG side by side
| ADA | WCAG | |
|---|---|---|
| What it is | US federal civil rights law | Technical guidelines for web content |
| Who publishes it | Congress; enforced through DOJ and the courts | W3C, through the Web Accessibility Initiative |
| What it says | People with disabilities must not be excluded or treated unequally | Specific, testable success criteria for pages and apps |
| Website detail | None in the statute itself | Contrast ratios, keyboard behavior, labels, captions and much more |
| Can you “pass” it? | That is a legal question for a lawyer or a court | A page either meets each criterion or it does not, so you can test and report conformance |
| Versions | Amended over time by Congress | 2.0, 2.1 and 2.2, each adding criteria |
The row that matters most is the fifth one. You can measure conformance with WCAG and write it down. Whether a business has met its duties under the ADA is not something an audit report can decide.
Levels A, AA and AAA in one minute
Every WCAG success criterion sits at one of three levels.
- Level A covers the most basic barriers, the ones that block people completely, such as images with no text alternative or controls that cannot be reached by keyboard.
- Level AA includes everything in A plus a further set, such as 1.4.3 Contrast (Minimum), 2.4.7 Focus Visible and, in version 2.2, 2.5.8 Target Size (Minimum).
- Level AAA is the strictest. It is not expected across an entire site, because some content cannot meet every AAA criterion.
AA is the usual target for business and government sites, and it is the level the Title II rule and Section 508 name and the one demand letters usually cite. If you want the structure of the standard explained properly, with the four principles and how criteria are numbered, read how WCAG is organized.
Which WCAG version should a US business aim for?
Three versions are in use, and each builds on the previous one.
- WCAG 2.0 is the version Section 508 incorporates. Still relevant if you sell to federal agencies.
- WCAG 2.1 added criteria for mobile use, low vision and cognitive needs, including 1.4.10 Reflow and 1.4.11 Non-text Contrast. It is the version in the Title II rule.
- WCAG 2.2 was finalized by the W3C in October 2023. Compared with 2.1 it has nine new success criteria, among them 2.4.11 Focus Not Obscured (Minimum), 2.5.8 Target Size (Minimum) and 3.3.8 Accessible Authentication (Minimum), and it removes 4.1.1 Parsing.
For most businesses open to the public, 2.2 AA is the sensible target. It is the current version, it includes the 2.1 criteria apart from the removed parsing check, and aiming for it means you will not need to redo the work when buyers and auditors catch up. If a contract, grant or government rule names a specific version, test and report against that version too. The full text is on the W3C’s WCAG 2.2 specification page, and our guide to the WCAG 2.2 AA requirements in practice translates it into things an owner can see.
What the difference means for your to-do list
The practical payoff of the ADA vs WCAG distinction is that the work splits cleanly into two lanes.
- Legal questions go to a lawyer. Whether the ADA applies to your business, how a court in your area might view your site, how to answer a demand letter. None of that is something a developer or an accessibility tester should answer for you.
- Technical questions are measured against WCAG. Which pages fail which criteria, how serious each failure is, what to fix first, and how to prove it was fixed. This is the job of a proper WCAG audit.
- The record joins the two lanes. A dated audit, a list of fixes and a retest against WCAG 2.2 AA are the things your lawyer can actually use if the question ever becomes legal.
Be careful with anyone who blurs the lanes. A tester who says your site is “ADA compliant” is stepping outside what testing can show. A lawyer who sends you a list of WCAG failures still needs someone technical to confirm and fix them. For an overview of the ADA duties themselves, see ADA compliance for websites in plain words, and for help with the technical lane across audits, fixes and monitoring, start with our website accessibility services.
Frequently asked questions
Is WCAG a law in the United States?
Not by itself. WCAG is a technical standard published by the W3C. It becomes a requirement when a rule or contract adopts it, such as the 2024 Title II rule, which adopts WCAG 2.1 AA for state and local governments, or Section 508, which incorporates WCAG 2.0 AA for federal agencies. For private businesses it is the usual benchmark rather than a written regulation.
If my site meets WCAG 2.2 AA, am I ADA compliant?
Meeting WCAG 2.2 AA shows that you have removed the barriers the most widely used standard describes, and documenting it is valuable. Whether that satisfies the ADA in your situation is a legal question, and courts have not all treated website cases the same way. Ask a lawyer about the legal side; use WCAG to measure the technical side.
Do I need to meet Level AAA?
No one expects AAA across a whole site, and the W3C itself notes that some content cannot meet every AAA criterion. AA is the level the Title II rule and Section 508 name, and the one demand letters usually cite. You can still adopt individual AAA criteria where they are easy wins for your audience, such as larger touch targets.
Why do some reports cite WCAG 2.1 and others 2.2?
Many letters, settlements and templates were written before 2.2 was published in October 2023, and the Title II rule names 2.1. Newer audits often use 2.2 because it is current. Since 2.2 builds on 2.1, aiming for 2.2 AA covers nearly everything in 2.1 AA, but ask for results against whichever version a contract names.
When you are ready to look at the technical lane properly, our ADA website compliance services page explains our audit, repair and record-keeping work, measured against WCAG 2.2 AA, while the legal side stays with your lawyer.
Next in this series: Does Accessibility Help SEO? The Honest Overlap
