WCAG vs ADA vs Section 508: the differences explained

The three names get used as if they were interchangeable, but they are different kinds of thing. WCAG, the Web Content Accessibility Guidelines, is a set of testable criteria for web content. The Americans with Disabilities Act (ADA) is a civil rights law that bars disability discrimination. Section 508 is part of the Rehabilitation Act and sets accessibility rules for the technology federal agencies develop, buy and use. They meet where a law needs a yardstick: the law says content must be accessible, and WCAG is the standard it points to. Mixing them up leads to wrong conclusions about who has to do what.

This page is general information, not legal advice. Whether a law reaches your organization is a question for a lawyer. Our guide to US web accessibility laws lists the rules and their sources.

WCAG, the ADA and Section 508 at a glance

The table compares what each one is, who it applies to and what it says about websites. The last row links the source for each column.

WCAG: the standard the laws point to

WCAG is developed by the Accessibility Guidelines Working Group, part of the W3C Web Accessibility Initiative, as W3C's WCAG 2 overview explains. It has three versions: 2.0 (published December 11, 2008), 2.1 (June 5, 2018) and 2.2 (October 5, 2023). Each later version adds success criteria without changing the earlier ones. W3C calls this backwards compatible and says content that conforms to WCAG 2.2 also conforms to 2.1 and 2.0. The one exception is 4.1.1 Parsing, which is obsolete in 2.2.

Every criterion sits at one of three levels, A, AA or AAA. The laws we track name AA when they name a level at all. WCAG A vs AA vs AAA explains the levels.

WCAG itself carries no penalty. W3C describes it as the document for people who want a technical standard, and it keeps a separate list of US laws and policies with the WCAG version each uses. In our reading, a site is held to WCAG only when something adopts it: a law, a contract, a settlement or the organization's own policy. W3C also notes that WCAG 2.2 is an ISO standard, ISO/IEC 40500:2025, which it says is exactly the same as the October 2023 version.

The ADA: a civil rights law, with a web standard only for governments

The ADA has separate parts, called titles. Title II covers state and local governments. Title III covers businesses open to the public, which the ADA calls public accommodations. Title III's main prohibition says no individual shall be discriminated against in the "full and equal enjoyment" of a public accommodation's goods, services and facilities (42 U.S.C. 12182(a)). The text of that section does not mention websites or any technical standard.

What the ADA means for websites comes from the Department of Justice (DOJ). Its guidance on web accessibility and the ADA, dated March 18, 2022, says the ADA applies to the web offerings of businesses and of state and local governments. It says DOJ has no regulation setting out detailed standards, and that existing technical standards, including WCAG and the Section 508 Standards, give "helpful guidance". It says businesses "have flexibility in how they comply", and that the guidance has no legally binding effect. The page notes that it does not reflect DOJ's 2024 rule for state and local governments.

Governments did get a standard. DOJ's Title II web rule names WCAG 2.1 Level AA as the technical standard for state and local government web content and mobile apps. After an extension, the compliance dates are April 26, 2027 for entities with a population of 50,000 or more, and April 26, 2028 for smaller entities and special district governments. Our ADA Title II deadline guide covers the dates and the exceptions, and Title II for local government covers what a web team must do.

Businesses under Title III have no such rule, so what the law requires is worked out case by case. A person who sues a business can ask a court for an injunction, which is an order to fix the barrier, and the court may award the winning side a reasonable attorney's fee (42 U.S.C. 12188 and 12205). When DOJ itself brings a Title III case, the court can impose civil penalties; our US laws page lists the amounts. For what to do if a complaint arrives, see responding to accessibility complaints.

One DOJ settlement shows what a standard can look like in practice. In its agreement with Meijer, signed February 2, 2022 and concerning the company's vaccine registration website, DOJ required conformance to WCAG 2.1 Level AA. That is one settlement, not a rule for every business. Our reading is that WCAG 2.1 AA is the usual working target for a business, and our guide to ADA website compliance for businesses covers what to do about it.

Section 508: the federal government's own rule

Section 508 requires each federal department and agency, when it develops, procures, maintains or uses electronic and information technology, to make that technology accessible to people with disabilities, unless doing so would impose an undue burden (29 U.S.C. 794d).

The technical rules are the Revised 508 Standards. The U.S. Access Board issued them in a final rule on January 18, 2017, and they have applied since January 18, 2018, according to Section508.gov. For web content they require conformance to Level A and Level AA of WCAG 2.0, as the Access Board's ICT page states. The standards cover information and communication technology (ICT), so they reach more than web pages. Our Section 508 guide covers documents, software and the other parts.

Section 508 binds federal agencies, not private companies directly. It reaches companies through what agencies buy. Section508.gov's FAQ on ACRs and VPATs says completing an Accessibility Conformance Report (ACR) is not optional for a vendor who wants the government to consider buying its product, and the VPAT template is the most common way to complete one. A software company that sells to a federal agency therefore answers to Section 508 through its buyer. See VPAT and ACR explained and accessibility in procurement. Separately, the statute lets an individual with a disability file a complaint with an agency about technology the agency procured (29 U.S.C. 794d(f)).

Which rule applies to which organization

Start from what kind of organization you are. The table shows the rule that usually reaches each kind and the web standard it names. It is a map, not a legal opinion.

Rules can stack. A company can sell to federal agencies, which brings Section 508 through procurement, and also run a public site that raises a separate Title III question. Other US rules exist too, such as the HHS Section 504 web rule and the Air Carrier Access Act rule; the US laws page lists them with sources.

Does meeting WCAG mean you meet the ADA?

Not automatically, and no one can certify it for you. For businesses the ADA names no standard, so WCAG conformance is a strong yardstick, not a legal safe harbor. That is our reading of DOJ's guidance, and a lawyer can tell you how it applies to your case.

A tool cannot settle it either. Automated checks find only part of WCAG (see how much of WCAG automated testing covers). In April 2025 the FTC finalized an order requiring accessiBe to pay $1,000,000. The FTC alleged that the company's claims that its product could make any website meet WCAG were false, misleading or unsubstantiated. That is why GotAlt does not claim to make a site conform to anything. Our page on overlays and the FTC says more.

Which WCAG version should you build to?

Treat the version a rule names as a floor and build above it. Section 508 names WCAG 2.0, the Title II web rule names 2.1, and no rule names a version for Title III. Because later versions keep the earlier criteria, building to WCAG 2.2 Level AA covers both versions those rules name, with the 4.1.1 Parsing caveat explained on which WCAG version the law requires. W3C encourages using the latest version of WCAG. See what is new in WCAG 2.2 and the WCAG 2.2 checklist.

Three mix-ups to avoid

• "WCAG is the law." It is a standard that laws, contracts and policies adopt. By itself it has no penalty.
• "Section 508 covers my company's website." Its duties fall on federal agencies. A private company meets it when an agency's buying process asks for it, not as a general duty.
• "The ADA requires WCAG 2.1 AA of every website." Only the Title II web rule names it, and that rule is for state and local governments. For businesses, no regulation sets a standard.

Check it yourself

Find out which rules may reach you, then test against the standard they point to.

• The Which accessibility laws apply to me? tool is a questionnaire that shows which laws may reach an organization, with a source for each. It is a starting point, not legal advice.
• The WCAG audit checklist lets you track all 55 Level A and AA criteria and export your progress as a CSV file.
• Scan my site for free runs automated rule checks on your pages and says what a scan leaves to a person. Automated checks cover part of WCAG; the rest needs a person.

Keep it checked

Whichever rule applies, a site that was fixed once can slip as pages and images change. GotAlt checks the pages you monitor every week. It compares each image's alt text with the image itself (up to six images per page), runs its rule checks, opens monitored pages in a browser for contrast and other render-dependent checks (see what we check), and reports what changed. Plans are from $69 a month. Audit my whole site from $69/mo.