WCAG compliance levels: Understanding A, AA and AAA

Why WCAG standards matter

Digital accessibility has become an essential part of every organisation’s online presence. Websites, apps and digital documents need to be designed so that everyone can use them — including people with visual, auditory, motor or cognitive impairments.

At the centre of this effort stand the Web Content Accessibility Guidelines (WCAG), developed by the World Wide Web Consortium (W3C). These internationally recognised standards define how digital content should be created to ensure equal access for all users. Understanding WCAG’s three conformance levels — A, AA and AAA — helps organisations decide how far to go in making their content truly inclusive.

The foundation of WCAG: POUR principles

Every WCAG requirement is based on four core principles known as POUR:

• Perceivable: Information must be presented in ways users can sense, such as providing text alternatives for images or captions for videos.
  

• Operable: Interfaces must be easy to navigate and operate, including by keyboard alone.
  

• Understandable: Content and navigation should be clear, predictable and consistent.
  

• Robust: Websites must work reliably with assistive technologies such as screen readers and voice control tools.
  

These principles remain constant across WCAG 2.0, 2.1 and 2.2, which together define 86 measurable “success criteria”.

The three WCAG conformance levels

WCAG is organised into three levels of conformance that build upon each other. Each level represents a deeper commitment to accessibility, moving from minimum requirements to comprehensive inclusion.

Level A: The basic foundation

WCAG A defines the essential barriers that prevent people with disabilities from using digital content. Meeting this level is the minimum step towards accessibility.

Examples include:

• providing text alternatives for non-text content

• ensuring keyboard accessibility

• adding form labels, and

• avoiding colour as the only way of conveying information.

A site that does not meet Level A will contain critical issues that block users entirely — for instance, an unlabeled button that a screen reader cannot identify. Achieving Level A compliance typically requires only minor technical changes, yet it lays the groundwork for higher standards.

Level AA: The global standard

WCAG AA has become the recognised benchmark for digital accessibility worldwide. Most accessibility laws and regulations — including the European Accessibility Act (EAA), the Barrierefreiheitsstärkungsgesetz (BFSG) in Germany, and the Accessibility for Ontarians with Disabilities Act (AODA) in Canada — refer to this level as the required standard.

Level AA expands upon the basics by addressing usability and readability for a wide range of users.

Examples include:

• maintaining sufficient colour contrast between text and background

• providing clear heading structures

• offering visible focus indicators

• ensuring responsive design, and

• supplying error messages that guide users through forms.

Achieving WCAG AA means a website satisfies all Level A and AA success criteria — around 50 in total under WCAG 2.2. For most organisations, this level represents the ideal balance between feasibility and inclusion.

Legal frameworks across Europe now enforce these principles. Since June 2025, the European Accessibility Act has made WCAG 2.2 Level AA the standard for public and private sector websites and key digital services across EU member states.

Beyond regulation, the motivation is clear: accessible websites provide better user experiences for everyone. Studies from WebAIM and the UK’s Office for National Statistics show that clear headings, consistent navigation and readable contrast ratios not only help users with disabilities but also improve engagement across all demographics.

Level AAA: The highest standard

WCAG AAA represents the most advanced level of accessibility. It requires meeting every criterion from Levels A and AA, plus an additional set of 28 enhanced requirements.

AAA criteria include:

• high contrast ratios (at least 7:1)

• sign language interpretation for videos,

• extended audio descriptions, and

• simplified language for complex information.

The W3C does not recommend Level AAA as a target for entire websites because some criteria cannot be applied universally.

However, implementing specific AAA features for critical content — such as checkout processes, medical forms or customer portals — can make a significant difference.

Organisations that combine AA compliance with selective AAA improvements demonstrate genuine commitment to inclusion and accessibility excellence.

Why WCAG compliance is worth the effort

Legal and policy context

Accessibility is now a legal requirement across much of the world. In the EU, the EAA and BFSG set clear obligations. In the United States, the Americans with Disabilities Act (ADA) increasingly uses WCAG 2.1 AA as the technical reference, supported by recent Department of Justice rulings.

Failure to address accessibility can lead to reputational and financial risk. Thousands of ADA-related digital accessibility lawsuits have been filed annually since 2020, affecting organisations of all sizes. But the real issue goes beyond compliance: inaccessible content excludes users and contradicts the principle of equal access.

Market reach and business impact

According to the World Health Organization, about 1.3 billion people — 16 percent of the global population — live with a disability. In the UK alone, the spending power of disabled households is estimated at more than £270 billion per year.

Research shows that inaccessible online shops lose billions annually in potential revenue. Around 70 percent of users with disabilities abandon websites they find difficult to use.

Conversely, accessible brands consistently outperform competitors in customer loyalty and satisfaction. Inclusive design improves conversion rates and strengthens brand reputation, while reducing the need for customer support — because users can complete tasks independently.

Better experience for everyone

Accessibility benefits all users, not only those with disabilities. Features such as keyboard navigation, mobile responsiveness, and clear structure improve usability for people browsing on smartphones, working in low-light conditions or facing temporary impairments.

Search engines also reward accessible design. Websites that follow WCAG principles tend to perform better in search rankings because accessibility overlaps with SEO best practices — descriptive alt text, structured headings, and semantic HTML all help search engines understand content.

The reality of accessibility today

Despite widespread awareness, accessibility on the web remains limited. Analyses by WebAIM and AudioEye show that more than 95 percent of homepages still contain detectable WCAG 2 failures.

The most common problems are missing image descriptions, poor contrast ratios, and unlabeled form fields.

With only a small share of websites currently meeting WCAG AA standards, organisations that act now gain a clear competitive advantage.

How to reach WCAG AA

Becoming WCAG AA compliant is achievable through a structured approach. Most organisations follow three main phases:

1. Establish the foundation: Fix critical issues such as missing alternative text, inaccessible forms, or poor keyboard navigation. Automated tools such as Eye-Able Report can help identify common errors, but manual testing is essential to capture the rest.
   

2. Reach Level AA: Address colour contrast, focus visibility, consistent navigation and error handling. Test your website across devices and input methods to ensure responsive behaviour and compatibility with assistive technologies.
   

3. Add selective AAA improvements: Prioritise key areas such as forms, logins or payments. Enhanced contrast, simplified content and additional media descriptions provide meaningful benefits for users.

Accessibility is not a one-time project but an ongoing process. Regular audits, user feedback and continuous monitoring help maintain and improve accessibility standards over time.

Not sure where to start? Find out how accessible your website is in 2 minutes – with our free WCAG accessibility check.

Looking ahead: WCAG 3.0

The W3C is developing the next generation of standards, known as WCAG 3.0, which will expand beyond web content to include mobile apps, software, virtual reality and connected devices.

The existing WCAG 2.2 conformance levels – A, AA and AAA – will not be carried over unchanged. The new model proposes a much more flexible approach to measuring accessibility, moving away from a rigid pass/fail system towards a graded scale that allows for more nuanced evaluation.

One widely discussed idea is the introduction of rating tiers such as Bronze, Silver and Gold, replacing the current A/AA/AAA levels. However, these categories are not yet formally defined as final standards – they are simply being explored as potential components of the new framework.

WCAG 3.0 also introduces updated methods for assessing colour contrast, including the Advanced Perceptual Contrast Algorithm (APCA), which is designed to deliver more accurate results in modern design environments such as dark mode.

The standard remains in draft form and has not yet been officially adopted as a W3C Recommendation.

Importantly, WCAG 2.2 continues to be valid and widely recognised. Organisations that currently meet Level AA are already well-positioned for future developments.

Conclusion: Accessibility as an ongoing commitment

Understanding WCAG compliance levels is more than a technical exercise. Level A ensures basic access, Level AA provides an inclusive experience for most users, and Level AAA represents excellence in accessibility.

By implementing WCAG AA now, organisations not only meet the expectations of the European Accessibility Act but also create digital environments that are more usable, inclusive and future-proof.

Accessible design fosters trust, strengthens customer relationships and reflects social responsibility. In a world where fewer than four percent of websites are considered accessible, taking action today sets your organisation apart.