Web Content Accessibility Guidelines: Understanding WCAG 2.0

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Web Content Accessibility Guidelines: Understanding WCAG 2.0

Posted March 14, 2025

AudioEye

Posted March 14, 2025

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WCAG 2.0 launched in 2008, but newer updates bring key changes. Explore WCAG 2.1, 2.2, and 3.0 and what they mean for accessibility.

Originally Published on September 21, 2015

Understanding WCAG 2.0

The Web Content Accessibility Guidelines (WCAG) were established by the World Wide Web Consortium (W3C) as a way to make digital content more accessible for individuals with disabilities. The guidelines were created nearly 30 years ago and continue to be refined as technology advances and user needs change.

The goals of WCAG are to:

  • Connect the world through common information technology and user experience standards.
  • Provide best practices for multiple types of devices and software.
  • Continually evolve and adapt accessibility guidelines through frequent review and support from the accessibility and disability community.

To ensure ongoing accessibility as technology advances, each version of WCAG expands on the previous version. For example, WCAG 2.0 guidelines expand on WCAG 1.0 which was released in 1999. WCAG 2.0 became an official recommendation in 2008 with WCAG 2.1 and WCAGA 2.2 following a few years later. The W3C has stated they will likely not release another version in the WCAG 2.0 series, such as WCAG 2.3. Instead, their focus has shifted to developing WCAG 3.0. The new version aims to provide more comprehensive and flexible guidelines to address new web technologies and accessibility needs.

WCAG 2.0 Hierarchy: 4 Principles, 12 Guidelines, 61 Testable Success Criteria, A, AA, AAA priority conformance levels, 450+ techniques

WCAG 2.0 Hierarchy

Principles: 4


Guidelines: 12

Testable Success Criteria: 61

Conformance Levels:

  • A (25)
  • AA (13)
  • AAA (23)

Techniques: These are recommendations on how to meet WCAG success criteria and provide web developers with practical guidance on how to implement accessible content.

WCAG 2.0 has 450+ and growing. 

Most techniques are technology-specific; for example, General, HTML, CSS, ARIA, etc. The types of techniques include:

  • Sufficient: Minimum requirements
  • Advisory: Additional improvements 
  • Failure: Often encountered mistakes

Some of the contents of techniques include:

  • Applicability
  • Description
  • Examples
  • Resources
  • Related techniques
  • Test (procedures)

For detailed criteria and a complete accessibility list, please visit the links provided in the sources below.

Principles & Guidelines: Perceivable, Operable, Understandable, Robust

Principles and Guidelines

WCAG is divided into four principles (known as the POUR principles) which help organizations apply accessibility guidelines more effectively — and build content that works for a larger audience. These principles include:

1. Perceivable

Both information and user interface components must be presentable to users in ways they can perceive.


For example, organizations should provide text alternatives (also called alt text) for non-text content so it can be understood by assistive technology users or add captions or transcripts to videos, audio descriptions, or other multimedia content so users who are deaf or hard of hearing can access video-only or audio-only content.

2. Operable

All user interface components and navigation on a website should be operable. This means all functionality should be available from a keyboard or other assistive technologies. Additionally, organizations should provide ways to help users navigate, find content, and determine where they are on a web page. Descriptive headers, consistent navigation, and avoiding keyboard traps are some of the ways web developers can achieve this.

3. Understandable

Information and the operation of the user interface must be understandable to a wide range of users. For example, all text content should be readable and understandable, and web pages should appear and operate in predictable ways. These guidelines help users avoid making mistakes or getting lost on a web page.

4. Robust

Content should be robust enough that it can be interpreted reliably by various user agents, including assistive technologies. This also means maximizing your website’s compatibility with both current and future agents to avoid potential disruptions.

For example, a website should use proper HTML semantics (such as <button> for buttons instead of <div> with click elements) to help screen readers correctly interpret and interact with the content, making it future-proof and compatible with different user agents.

The Five Conformance Requirements: 1. Conformance Levels 2. Full Pages 3. The Complete Process 4 & 5. Usability of Accessibility Supported Technologies

The Five WCAG Conformance Requirements

For organizations to meet WCAG conformance standards (which are enforced by accessibility laws like the Americans with Disabilities Act (ADA) and the European Accessibility Act (EAA)), they must meet the five requirements below:

1. Conformance Level

There are three levels of conformance:

  • Level A: This is the minimum degree of accessibility and covers basic web accessibility. 
  • Level AA: This is considered the international standard of accessibility and addresses the most common barriers people with disabilities encounter online. 
  • Level AAA: This is the highest degree of conformance and is considered the uppermost level that can be reached for accessibility. This includes providing additional accessibility features such as videos with sign language interpretation or enhanced color contrast ratios.

It’s important to note that if you have conformance at a higher WCAG level, you’ll have conformance at the lower levels. For example, if you comply with Level AA, you also comply with Level A. If you comply with Level AAA, you’re also complying with Level A and Level AA.

2. Full Pages

Full pages must meet the conformance level requirements (either A or AA). Certain elements of the page cannot be excluded, such as headings, images, table of contents, abbreviations, menus, etc.

3. Complete Process

If a web page is one of a series of web pages that represents a particular process (e.g., users have to complete a series of steps on various web pages to accomplish an activity), all pages must meet the same conformance level.

4. Accessibility-Supported Ways of Using Technologies

Web content must use technologies in a way that is accessibility-supported, meaning they work reliably with assistive technologies (like screen readers) and built-in accessibility features of browsers. This ensures that users with disabilities can perceive, operate, and understand the content. If a technology is used in a way that is not widely supported by assistive tools, it is not considered conformant with WCAG.

5. Non-Interference

If the web page uses technology that is not accessibility supported, it must not block or create barriers for technology that is accessibility supported.

WCAG 2.0 vs. 2.1 vs. 2.2

As mentioned above, the W3C has released various versions of WCAG to address new technologies and ensure ongoing accessibility. Currently, WCAG 2.X is the most widely used. 

WCAG 2.0 has 61 success criteria with WCAG 2.1 adding 17 success criteria in 2018. Below are some of the key success criteria introduced in WCAG 2.1 that were not included in WCAG 2.0:

  • Orientation: Ensures that users are not restricted from viewing content when they change their device’s orientation (e.g., switching between portrait and landscape mode).
  • Text spacing: Requires that content using markup languages supports user modification to text spacing, improving readability for those with visual or cognitive disabilities.
  • Label in name: Ensures that if a web label includes visible text or an image of text, the programmatic name should match the visible label to improve accessibility for voice control and screen reader users.
  • Time adjustments: Requires that users should be able to turn off, adjust, or extend time limits for time-based media, preventing accessibility barriers and ensuring users have enough time to interact with content.

More recently, WCAG 2.2 was released in October 2023, adding another nine success criteria to improve accessibility for users with cognitive and motor disabilities. Some of these criteria include:

  • Focus not obscured: Ensures that interactive elements, like buttons and links, remain visible when they receive keyboard focus.
  • Dragging movements: Requires that any functionality using dragging movements (e.g., sliders or drag-and-drop actions) can also be operated through a simple click or tap. 
  • Target size: Defines a minimum size for clickable elements to prevent accidental clicks, improving usability for people with limited dexterity.
  • Consistent help: Ensures that help mechanisms (such as live chat or contact forms) remain consistently available across pages. 

While there are no plans for a WCAG 2.3, efforts are now focused on developing WCAG 3.0, which is currently in development. As of the time of this writing, WCAG 3.0 does not have an official release date and is expected to take several years before becoming a finalized recommendation.

Who Needs to Conform to WCAG 2.0?

While every organization should strive to provide the best possible experience to people with disabilities, WCAG 2.0 conformance is enforced in several accessibility laws. The U.S. Department of Justice (DOJ), for instance, has repeatedly stated that conformance with WCAG 2.1 Level AA is required to be considered compliant with the ADA and Section 508 of the Rehabilitation Act. The European Union also uses WCAG 2.1 Level AA to measure compliance with the EAA.

Put simply: if you’re creating digital content — websites, mobile apps, web-delivered documents, user interfaces, or any other type of digital content — the best practice is to use WCAG 2.1 Level AA to ensure your online content is accessible and compliant with accessibility laws.

WCAG 2.0: An Internationally Accepted Standard

WCAG has been embraced as the international standard and has been directly referenced or adopted by at least 14 countries and the European Union. Some examples:


While penalties for noncompliance may vary, most countries allow people with disabilities to file lawsuits against non-compliant businesses. For example, in the U.S., digital accessibility lawsuits filed under the ADA have increased significantly in the last decade — and since most websites fail to meet WCAG’s basic requirements, that trend will likely continue.

How to Improve Web Accessibility and Conform with WCAG 2.0

While the goal of web accessibility is to remove any and all barriers that prevent users from easily navigating your site, it’s important to remember accessibility is not a one-and-done checklist. Because accessibility laws and standards are evolving, it’s crucial to regularly audit your website for accessibility issues to ensure ongoing compliance. 

In addition to regular audits, the following strategies can help improve your overall accessibility.

Follow Web Accessibility Best Practices

When designing for accessibility, ensure you’re following the latest WCAG requirements. Your digital content should include as many WCAG success criteria as possible, including:

  • Ensure your website is screen reader friendly: To ensure compatibility with screen readers, ensure you’ve defined your website’s language, added alt text to images, and created a logical order for site information.
  • Provide error messages: When errors occur, ensure you have clear error identification and error suggestion messages. This helps users understand where the error occurred, what steps need to be taken to resolve it, and helps with future error prevention.
  • Write alt text for images: Alt text ensures users with low vision or other vision impairments can browse and utilize your site. 
  • Use the right color palette: The use of color on your website can increase or decrease accessibility. For example, visitors with vision impairments may find it difficult to differentiate between web elements. Utilizing an accessible color palette and balancing color contrast ratios can help improve readability for these users and conform to Level AA regulations.
  • Choose clear fonts: Font types can make all the difference on your website. Choose fonts that are clear and easy to read, such as Times New Roman, Arial, or Helvetica. This is especially beneficial for those with cognitive or learning disabilities like Dyslexia.
  • Reduce unnecessary movement: Users with motion-related disorders (i.e. epilepsy or ADHD) can become confused when web elements move at various speeds. To avoid this, reduce unnecessary motion by avoiding parallax scrolling or limiting autoplay functionality. Keep flash thresholds to a minimum as well.
  • Enable visual indicators: Visual indicators help to focus attention when users use a keyboard to navigate web pages. Essentially, the tool enables readers to see their location and guides them throughout the site.
  • Make documents accessible: Ensure online documents such as Word, PDFs, or HTML documents are in an accessible format. You can improve the accessibility of documents by using headings, adding alt text with the document’s language, and using descriptive hyperlinks.
  • Ensure good keyboard accessibility: Users should be able to navigate your digital content through keyboard commands and shortcuts alone. 
  • Use descriptive link text: All hyperlinks should have descriptive link text that accurately describes the purpose of each link, helping users understand its purpose and what will happen when it’s clicked. 

For a more comprehensive list of the accessibility features included in WCAG, check out our WCAG 2.1 checklist.

Use Solutions to Test and Improve Accessibility

Accessibility tools can help determine the universality (aspects of your site that are usable for everyone) and usability (simplicity and functionality of design elements) of your site. More simply — these tools can help you get an understanding of how accessible your existing content is and where improvements are needed. This can help you streamline your path to compliance with accessibility laws.

For example, AudioEye provides numerous accessibility tools, both free and paid, to enhance the accessibility of your content. From our free Web Accessibility Scanner that identifies 30 WCAG violations (more than any other tool on the market) to our Automated Fixes that automatically resolve these issues, AudioEye simplifies and streamlines your path to more accessible and compliant content.

Create More Accessible, Compliant Digital Content with AudioEye

Embracing WAG enables you to create a better, more accessible online experience for your users while simultaneously lowering your legal risk. Following the accessibility best practices mentioned above is a great starting point. However, to create digital content that’s truly accessible and compliant, you need the right tools.

That’s where AudioEye comes in. No matter where you are in your accessibility journey, AudioEye provides the tools, expertise, and support needed to conform with WCAG and meet accessibility compliance requirements. We do this by taking a three-pronged approach to accessibility, using human-assisted AI technology, audits with experts from the disability community, and testing during the development process. Our approach to accessibility enables you to detect and fix more accessibility issues and achieve industry-leading compliance with accessibility standards. Plus, with AudioEye Assurance, you’ll enjoy a level of protection that’s 400% better than consulting or automation-only approaches.


Ready to take the first step? Use our free Web Accessibility Checker to see how accessible your existing content is.

Source Materials

World Wide Web Consortium
Introduction to WCAG
Understanding Conformance

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