What’s the difference between WCAG conformance levels (A, AA, and AAA)?

Have you ever been confused about the different levels of conformance in the Web Content Accessibility Guidelines (WCAG) or wondered which one is right for your organization? Here’s a quick explanation to clear up the confusion.

Level A (Essential):

This is the minimum level of accessibility. It addresses the most critical barriers that would prevent users from accessing content. These requirements are generally achievable without significant design changes and solve major accessibility problems.

Level AA (Standard):

This is the level most organizations aim for and is considered the industry standard. It includes all Level A requirements plus additional features that make content more accessible to a wider range of users. Level AA has been established as the conformance standard in major government legislation, including the Americans with Disabilities Act (ADA), the Accessibility for Ontarians with Disabilities Act (AODA), and the European Accessibility Act (EAA).

Level AAA (Enhanced):

This is the highest and most rigorous level of accessibility support. It includes all Level A and AA requirements plus additional enhancements that make content accessible to the broadest possible audience. Level AAA compliance for an entire website is not realistic for most organizations due to its complexity. Instead, organizations typically aim for Level AAA compliance for specific content or features.

Progressive Support

Many of the success criteria in WCAG build upon requirements found in lower conformance levels. For example, color contrast requirements between normal text and backgrounds become more stringent at each level: Level A has no contrast requirement, while Level AA requires a contrast ratio of 4.5:1, and Level AAA requires 7:1. The Level AAA requirement aims to support a wider range of users, such as those with severe low vision or those without access to contrast-enhancing assistive technology.

When in doubt, aim for WCAG Level AA compliance. It provides a robust level of accessibility while remaining achievable for most organizations.