ADA vs WCAG: What's the Difference and Why It Matters

What is the ADA?

The Americans with Disabilities Act (ADA) is a US federal civil rights law signed in 1990. It prohibits discrimination against individuals with disabilities in employment, state and local government services, public accommodations, commercial facilities, transportation, and telecommunications.

For the web, the most relevant part is Title III, which covers “places of public accommodation” owned or operated by private entities. Courts across the US have ruled, time and again, that commercial websites are places of public accommodation — or at least sufficiently connected to one — and therefore must be accessible to people with disabilities.

The ADA does not, however, prescribe how a website must be made accessible. It does not name WCAG. It does not define a technical standard. What it says is that discrimination is illegal, and courts decide case by case whether a given site meets the bar. That gap is what WCAG fills.

What is WCAG?

The Web Content Accessibility Guidelines (WCAG) are developed by the Web Accessibility Initiative (WAI) of the World Wide Web Consortium (W3C). They are the international reference for web accessibility. They are not a law. They are a technical specification that defines what it means, concretely, for web content to be accessible.

WCAG is organised around four principles: content must be Perceivable, Operable, Understandable, and Robust (POUR). Under these principles are guidelines, and under each guideline are testable success criteria grouped into three conformance levels:

• ✓Level A — the minimum. Without it, entire groups of users cannot access your content at all.
• ✓Level AA — the standard target for most regulations, including ADA case law and the European Accessibility Act.
• ✓Level AAA — the highest level, generally not required except for specialised content.

WCAG has gone through multiple versions: 1.0 (1999), 2.0 (2008), 2.1 (2018), and 2.2 (2023). WCAG 2.1 added success criteria for mobile accessibility, low vision, and cognitive disabilities. WCAG 2.2 added nine more criteria, mostly around authentication and dragging gestures.

How WCAG relates to ADA compliance

Because the ADA does not define a technical standard, courts and regulators needed a reference. They chose WCAG. Here is how the link was cemented:

• ✓Case law. Settlements and rulings in ADA web cases — from Netflix to Target to Domino’s — reference WCAG 2.0 or 2.1 Level AA as the benchmark.
• ✓DOJ guidance. The Department of Justice repeatedly identified WCAG 2.1 AA as the appropriate standard before publishing a formal rule.
• ✓2024 DOJ final rule. In April 2024, the DOJ published a final rule (28 CFR Part 35) requiring state and local government websites and mobile apps to meet WCAG 2.1 AA. It directly applies to public entities, but it reinforces 2.1 AA as the benchmark for ADA web accessibility.
• ✓Demand letters. Plaintiffs’ firms use WCAG as the testing framework in demand letters. If your site fails WCAG 2.1 AA, you have no practical defence against an ADA web lawsuit.

In short: the ADA tells you that your site must be accessible. WCAG tells you how. Meeting WCAG 2.1 AA is the most defensible way to demonstrate ADA compliance today.