What is Web Accessibility (WCAG)?

The Web Content Accessibility Guidelines (WCAG) are the international standard for making websites usable by people with disabilities, published by the World Wide Web Consortium (W3C). WCAG is not a law. It is a technical specification: a numbered set of testable success criteria that say what accessible web content has to do, organized under four principles (perceivable, operable, understandable, robust) and graded at three conformance levels (A, AA, AAA). Laws such as the Americans with Disabilities Act and Section 508 point at WCAG as the measuring stick, which is why ADA compliance for a website almost always means “conforms to WCAG at Level AA.”

Every site we build is developed to WCAG 2.1 AA, and our ADA compliance services audit and remediate existing sites against the same standard.

What WCAG covers

WCAG applies to web content: pages, documents, applications, media and the code that delivers them. It does not cover the operating system, the browser or the assistive technology itself; those have their own standards. Within that scope, it addresses the full range of disabilities that affect web use.

• Visual: blindness, low vision and color-vision deficiency, addressed through text alternatives, contrast, resizable text and screen-reader compatibility.
• Motor: limited use of a mouse or touchscreen, addressed through keyboard operability, target size and time limits.
• Auditory: deafness and hearing loss, addressed through captions, transcripts and visual alternatives to audio cues.
• Cognitive and neurological: addressed through consistent navigation, clear instructions, error prevention and limits on motion and flashing content.

How the guidelines are organized

WCAG has three layers. The top layer is the four principles, often abbreviated POUR. Under them sit 13 guidelines, which are broad goals such as “provide text alternatives for any non-text content” or “make all functionality available from a keyboard.” Under the guidelines sit the success criteria, and those are the part that matters in practice: each one is a specific, testable statement, numbered like 1.4.3 (Contrast, Minimum) or 2.4.7 (Focus Visible), with a conformance level attached. Our WCAG 2.2 checklist lists all 55 Level A and AA criteria with a plain-language explanation of each.

When an auditor says a site “fails 1.1.1,” they mean a specific success criterion (in that case, images without text alternatives), not a general impression. That precision is what makes WCAG usable as a contractual and legal standard.

Conformance levels: A, AA and AAA

• Level A is the floor. Its criteria remove barriers that make a site impossible to use for some people: keyboard access, alt text, no keyboard traps, no content that flashes more than three times a second.
• Level AA is the working standard. It adds the criteria that make a site usable in practice: a 4.5:1 contrast ratio for normal text, visible focus indicators, consistent navigation, text that can be resized to 200 percent, captions for recorded video. AA is the level referenced by the ADA regulations, Section 508 and the European standard EN 301 549, and it is the level to aim for.
• Level AAA is the ceiling. It includes criteria such as 7:1 contrast, sign-language interpretation for video and reading-level limits. The W3C itself says AAA is not achievable for all content, and it is rarely required.

Conformance is measured per page and is all-or-nothing at each level. A page conforms to AA only if it meets every A and AA criterion; there is no partial credit. If a task spans several pages (a checkout, an application form), every page in the process has to conform for the process to count.

WCAG versions: 2.0, 2.1 and 2.2

WCAG is versioned, and each version is backward compatible: a site that conforms to 2.2 also conforms to 2.1 and 2.0.

• WCAG 2.0 (December 2008) established the POUR structure and the A/AA/AAA levels. Section 508 in the United States still references 2.0 AA.
• WCAG 2.1 (June 2018) added 17 criteria, mostly for mobile use, low vision and cognitive disabilities: text spacing, reflow at 320 pixels wide, orientation, pointer gestures, status messages. This is the version the ADA Title II rule and most current legal settlements cite.
• WCAG 2.2 (October 2023) added nine criteria and retired one (4.1.1 Parsing), for 86 in total: 31 at Level A, 24 at AA and 31 at AAA. The new AA criteria are the ones most likely to affect an existing site: focus not obscured by sticky headers, a minimum target size of 24 by 24 pixels, alternatives to dragging, consistent placement of help, no re-entering information already provided, and accessible authentication without cognitive tests. WCAG 2.2 is also an ISO standard, ISO/IEC 40500:2025, identical to the October 2023 text; the W3C has since published errata updates to both 2.2 and 2.1 that correct wording without changing any criterion.

WCAG 3.0 has been in draft for several years and uses a different scoring model; the latest Working Draft was published in September 2026. It is not a standard yet, nothing references it, and the W3C says it will not supersede WCAG 2. Build to 2.2 AA today and 2.1 AA is covered.

WCAG and the law

WCAG becomes legally meaningful when a law or regulation adopts it. In the United States, four do most of the work.

• ADA Title III (businesses open to the public) has no written web standard, but courts and Department of Justice settlements have consistently used WCAG 2.0 or 2.1 AA as the benchmark. This is the basis of most website accessibility lawsuits.
• ADA Title II (state and local government) got a formal rule in April 2024 that names WCAG 2.1 AA as the required standard for public-sector websites and apps. On April 20, 2026 the Department of Justice pushed the compliance dates back a year: April 26, 2027 for entities serving 50,000 or more people, and April 26, 2028 for smaller entities and special districts. The standard did not change, only the dates.
• Section 504 (HHS) applies the same WCAG 2.1 AA standard to healthcare organizations that receive federal funding, with deadlines of May 11, 2027 for organizations with 15 or more employees and May 10, 2028 for smaller ones, after a similar extension in May 2026.
• Section 508 (federal agencies and their vendors) requires WCAG 2.0 AA. Vendors document their conformance in a VPAT.

Outside the United States, the European Accessibility Act and EN 301 549 reference WCAG 2.1 AA, and Canada, the UK and Australia have adopted it in their own regulations. The practical takeaway is the same everywhere: WCAG 2.1 AA (or 2.2 AA, which includes it) is the level that satisfies the law, and it is the level a court will ask about.

How WCAG conformance is tested

Automated scanners such as axe, WAVE and Lighthouse are the right place to start, and they are fast: they reliably catch missing alt text, contrast failures, missing form labels and broken heading order. But they only detect the criteria that can be checked by code. Whether alt text is actually meaningful, whether a custom dropdown works with a screen reader, whether focus order makes sense and whether an error message tells the user how to fix the problem all require a person.

A real WCAG audit therefore combines three things.

• Automated scanning of every template, to catch the mechanical failures at scale.
• Manual testing with a keyboard only, with a screen reader (VoiceOver, NVDA or JAWS), at 200 percent zoom and at 320 pixels wide.
• A criterion-by-criterion report that lists each failing success criterion, where it fails and how to fix it, which is what a compliance officer or a lawyer needs to see.

Accessibility overlays and widgets that promise WCAG conformance from a single script do not deliver it. They cannot fix code structure, they often interfere with the assistive technology people already use, and sites running them have been sued anyway. For The Trust Company of North Carolina, we built WCAG AA conformance into the theme and then had it verified by independent third-party audit tooling rather than self-certifying, which is the difference between claiming conformance and being able to show it.

WCAG and SEO

Most WCAG work is also technical SEO work. Semantic HTML, a single H1 and a logical heading hierarchy, descriptive alt text, labeled forms, captions and transcripts, and readable text on mobile are all WCAG success criteria, and every one of them is also something Google and AI search systems use to understand a page. A site built to WCAG AA is, almost by definition, a well-structured site. Our semantic HTML cheat sheet covers the markup that serves both.

If you want to know where your site stands, our ADA compliance website checklist walks through the highest-impact WCAG criteria in plain language, ten checks you can do yourself takes about 30 minutes, and our ADA compliance services handle the audit and the fixes. Book a discovery call to get a straight answer on your current conformance level and what it would take to reach AA.