Understanding the Difference Between WCAG A, AA, and AAA Conformance

Digital accessibility is now central to how new technologies are built, and the World Wide Web Consortium (W3C) created the Web Content Accessibility Guidelines (WCAG)(opens in a new tab) to set the standard. The guidelines are divided into three levels of conformance to show how well a site meets accessibility standards.

Below, we'll discuss the differences between each WCAG conformance level and the standards each one includes. We'll also explain which conformance level you should strive for to comply with accessibility laws and provide an accessible, inclusive experience for users.

Overview of the WCAG Conformance Levels A vs. AA vs. AAA 

The three WCAG levels are built around four core principles, known as POUR: content must be Perceivable, Operable, Understandable, and Robust. 

Every success criterion across all three conformance levels maps back to one of these principles:

• WCAG Level A: The minimum level of conformance, Level A contains basic success criteria for removing serious accessibility barriers that affect a wide range of users. 

• WCAG Level AA: Level AA removes additional barriers and establishes a level of accessibility that works for most devices and assistive technologies, such as screen readers.

• WCAG Level AAA: The most strict level of conformance, Level AAA contains additional success criteria to establish the highest possible level of website accessibility.

The difference between Level A, AA, and AAA is not which principles they cover, but how thoroughly they address each one. As you move up the levels, the criteria become more demanding and cover a wider range of user needs and assistive technologies.

These principles apply across WCAG 2.1 and the latest version, WCAG 2.2, which introduced additional criteria but kept the same three-level structure. The table below provides an overview of each level.

Which WCAG Compliance Level Should Organizations Follow?

For most organizations, WCAG Level AA is the appropriate target. It balances accessibility impact with practical implementation effort. Level AA is widely adopted, legally defensible under the ADA, and compatible with the vast majority of assistive technologies.

Level A compliance alone may leave your organization vulnerable to accessibility lawsuits, as it does not address many common barriers that affect users with disabilities.

Level AAA compliance is valuable for specific contexts such as educational institutions, government agencies, or organizations serving users with high accessibility needs. However, it should not be viewed as a blanket requirement for all websites.

If you're uncertain which level applies to your organization or want to understand your current conformance status, an expert accessibility audit can clarify your requirements and identify a compliance roadmap.

WCAG Level A vs. AA: What Accessibility Issues are Covered?

Level A is considered the least strict conformance level. It includes success criteria that help you avoid the most serious of accessibility issues that can prevent users with disabilities from effectively using digital content. Some of these criteria include:

• Keyboard commands and shortcuts that allow users to navigate digital content by a keyboard alone.

• Alternative text (alt text) is provided for images or other non-text content.

• Forms include clear labels or instructions on how to complete them correctly.

• Digital content is optimized for assistive technologies, including screen readers.

• Information is not portrayed through color alone.

Examples of WCAG 2.1 Level AA Success Criteria

Level AA builds on the success criteria included in Level A and enhances accessibility for users in various contexts. Level AA includes 20 additional criteria to provide a better experience for users with disabilities. These criteria cover essential user experience (UX) issues, such as:

• Color contrast: Maintaining at a minimum a color contrast ratio of 4.5:1 between text and background elements.

• Logical subheads: Writing subheadings that are organized logically (i.e., H1, H2, H3, etc.).

• Consistency: Keeping navigation mechanisms (such as header and footer links) consistent from page to page.

• Operability: Ensuring content is operable in different display orientations, and fully operable for keyboard users

• Video captioning: Providing captions for video content

WCAG AA vs. AAA: What Level of WCAG Conformance Is Recommended?

The W3C recommends conforming to WCAG 2.1 Level AA. WCAG 2.1 Level AA is the most widely implemented standard, and the benchmark most organizations are working toward. Websites that meet all Level AA success criteria are generally considered accessible for most users with disabilities.

As mentioned above, WCAG Level AAA is considered the most strict conformance level. The success criteria included in this level are more technical and detailed.

How Do You Test Content for WCAG Level AA Conformance?

If you're looking to test your digital content for WCAG conformance, there are two main approaches: you can test your content against WCAG success criteria yourself or use accessibility testing tools.

Automated Accessibility Testing

Automated accessibility testing involves using accessibility testing tools to automatically scan your digital content for WCAG violations. Most tools will scan your content's code to find common accessibility issues and flag them in a report.

While automated accessibility testing can save you time, it does have some limitations. The biggest one being that automated tools can only test for common WCAG violations. More complex issues—ones that can significantly impact the user experience—may only be identified through manual testing.

For example, automated tools can check images to see if images include alt text. However, these tools can't report on the quality of the alt text and whether it's actually helpful to users.

Manual Accessibility Testing

Manual testing, or expert testing, addresses accessibility barriers that automated tools can't catch. Where automated testing excels at flagging code-level issues at scale, manual testing evaluates whether your content is actually usable — checking things like:

• Keyboard-only navigation

• Screen reader compatibility

• Alt text accuracy

• Heading and subheading order

• WCAG success criteria compliance

The tradeoff: manual testing is time-consuming, expensive, and only captures a snapshot of your site at a single point in time. New content means new testing, and involving users with disabilities — while valuable — doesn't eliminate the time cost of reviewing everything thoroughly.

That's why most accessibility experts recommend combining manual and automated testing to audit your site for WCAG 2.1 conformance. Automation handles speed and scale; human testers catch the nuanced, complex issues that software alone can't reliably identify.

Determining Your Organization's WCAG Conformance Requirements

Understanding which WCAG conformance level applies to your organization is the first step, but knowing where you currently stand requires more than a quick read of the guidelines.

Start by scanning your site. A free automated scan can surface common WCAG violations quickly and give you a baseline picture of your accessibility status before you invest in deeper remediation.

From there, the path forward depends on your organization's legal obligations, user base, and risk tolerance. Organizations subject to ADA Title III, Section 508, or the European Accessibility Act typically need to target at least WCAG 2.1 Level AA, but the right conformance level isn't always obvious, and a roadmap that works for one organization may not fit another.

If your scan surfaces issues you're not sure how to prioritize — or if you need expert guidance on what your results actually mean — AudioEye's accessibility experts can assess your current status, identify the right conformance target, and help you build a clear plan to get there.

Book Your Demo with a WCAG Compliance Expert →