WCAG (Web Content Accessibility Guidelines) is a globally recognized set of guidelines developed by the World Wide Web Consortium (W3C) to make web content accessible to people with disabilities. It’s a set of recommendations on how to design and develop websites, web applications, and other digital content to be usable by everyone, regardless of their abilities.
The first version, WCAG 1.0, was released in 1999. It was followed by WCAG 2.0 in 2008, and WCAG 2.1 in 2018. The latest version, WCAG 2.2, was finalized in October 2023, with further updates already in discussion as accessibility technology evolves.
Why WCAG Should Matter to You
People living with disabilities (such as visual, auditory, physical, speech, cognitive, language, learning, and neurological disabilities) often face barriers when using websites and digital tools. WCAG provides specific, testable criteria to remove those barriers. These guidelines help ensure that websites are easily usable for all.
Following WCAG isn’t just the right thing to do. It can also protect your business from legal issues and expand your potential audience.
Who Maintains and Updates the WCAG?
The WCAG guidelines are maintained by the World Wide Web Consortium (W3C), specifically through its Web Accessibility Initiative (WAI). WAI includes accessibility experts, researchers, developers, and stakeholders from around the world who collaborate to revise and improve the guidelines.
WCAG Guiding Principles
The Web Content Accessibility Guidelines (WCAG) are built around four foundational principles that ensure digital content is accessible to all users, including those with disabilities. These principles are Perceivable, Operable, Understandable, and Robust. Every guideline and success criterion within WCAG ties back to one or more of these principles.
1. Perceivable
This principle states that users must be able to perceive the information being presented with at least one of their senses. it can’t be invisible to all of their senses.
In simpler terms, content must be available in multiple formats so that users with different abilities can access it. This includes visual, auditory, and tactile formats. For example, someone who is blind may need text alternatives to images, while someone who is deaf may need captions for videos.
2. Operable
The operable principle ensures that users can interact with and navigate the interface of the website, regardless of how they control their devices. This is especially important for users who rely on keyboard navigation, voice control, or alternative input devices.
3. Understandable
This principle ensures that content is not only available and operable, but also easy to understand. This applies to both the information presented and the operation of the interface. The website layout should be consistent and its content should be clear and understandable.
4. Robust
Content must be built to work with a wide variety of user agents, including current and future technologies such as screen readers, voice browsers, and mobile devices. This involves use of clean HTML/CSS code, proper use of ARIA roles and attributes to enhance accessibility for dynamic content and complex interfaces.
WCAG Levels of Conformance
The WCAG guidelines are structured into three levels of conformance. Each level represents an increasing degree of accessibility and technical compliance.
Level A: Basic Accessibility
This is the minimum level of accessibility. It addresses the most fundamental barriers to access for users with disabilities. Without Level A compliance, many users will be unable to use or navigate your content at all.
Requirements include:
- Providing text alternatives for non-text content (images, icons, etc.)
- Making content navigable via keyboard
- Ensuring users are not trapped in any component while using a keyboard
Level AA: Recommended Standard
This is the standard most organizations aim to meet. Level AA addresses common and significant barriers, helping ensure that content is accessible to a broader range of users.
Additional requirements include:
- Minimum contrast ratios between text and background (4.5:1 for normal text)
- Clear and consistent navigation across pages
- Resizable text without loss of content or functionality
- Providing visible focus indicators for interactive elements
Level AAA: Enhanced Accessibility
This level offers the highest level of accessibility and includes criteria that accommodate users with the most severe disabilities. However, it is often not practical or possible to meet all Level AAA criteria for every piece of content.
Requirements include:
- Sign language interpretation for all pre recorded audio content
- Enhanced contrast (7:1) for better readability
- More advanced error prevention and input support
Success Criteria Explained
Each level of WCAG conformance contains a series of Success Criteria i.e specific, measurable requirements that determine whether a site meets the guidelines. These criteria are written in a clear, testable format and allow for both automated and manual evaluation.
Here are some key success criteria from WCAG 2.2:
Non-text Content (1.1.1)
Requirement: All non-text content (images, charts, icons, buttons) must have a text alternative that serves the same purpose. This ensures users who cannot see images or visual elements can still understand their function or meaning.
Keyboard Accessible (2.1.1)
Requirement: All functionality on a website must be available via keyboard input alone. This is critical for users who cannot use a mouse due to mobility impairments.
Contrast Minimum (1.4.3)
Requirement: Text and interactive elements must have a contrast ratio of at least 4.5:1 against the background for normal text and 3:1 for large text. This helps users with low vision or color blindness read text more easily.
Focus Visible (2.4.7)
Requirement: When users tab through interactive elements (like links or buttons), the element they are focused on must be clearly visible. It ensures keyboard users can see where they are on the page.
Error Identification (3.3.1)
Requirement: If an input error is detected, the error must be identified and described to the user in text. It’s to assist users with cognitive disabilities or those using assistive tech in correcting mistakes.
There are over 80 success criteria in WCAG 2.2, grouped by principle and level. These criteria serve as the foundation of digital accessibility evaluations and help organizations build inclusive digital experiences.
By understanding and applying the principles, levels, and success criteria of WCAG, businesses and developers can create websites and applications that are truly accessible to all users, regardless of their abilities.
Tips for WCAG Compliance
- Use semantic HTML tags like , , and provide structure for assistive technologies.
- Use ARIA roles only when native HTML elements can’t do the job.
- Provide text alternatives for every non-text element.
- Ensure sufficient color contrast. Use tools like the Contrast Checker to meet AA/AAA requirements.
- Make all functionality keyboard accessible
- Use descriptive links. Avoid “click here” and use context-aware link text.
- Test with Real Users. Involve users with disabilities in your accessibility testing process.
- Perform regular audits. Accessibility isn’t one-and-done so use tools and manual checks to maintain compliance.
Frequently Asked Questions (FAQs)
Q: Is WCAG compliance required by law?
A: Not directly. However, many laws like the ADA (U.S.), EN 301 549 (EU), and AODA (Canada) refer to WCAG as the standard to meet.
Q: What version of WCAG should I follow?
A: Most legal references currently point to WCAG 2.0 Level AA, but WCAG 2.2 is the most updated and should be followed for future-proofing.
Q: Can I be sued for not complying with WCAG?
A: Yes. Inaccessible websites have led to thousands of lawsuits, particularly in the U.S. under the ADA.Q: Does WCAG apply to mobile apps too?
A: Yes. The principles and many success criteria apply to mobile web and native apps.
