Web Content Accessibility Guidelines: Understanding WCAG 2.0

The Web Content Accessibility Guidelines(opens in a new tab) (WCAG) were established by the World Wide Web Consortium(opens in a new tab) (W3C) to make digital content more accessible to individuals with disabilities. 

WCAG guidelines were created nearly 30 years ago and continue to be refined as technology advances and user needs change. Below, we’ll explore the key differences between WCAG 2.0 and newer versions, as well as which version organizations should follow to ensure compliance with key accessibility laws.

What is WCAG?

As mentioned above, WCAG is a set of internationally recognized standards that explain how to design and develop digital content so people with disabilities can perceive, navigate, and interact with it effectively. Created by the W3C, WCAG serves as the technical foundation for most website accessibility laws and practices worldwide.

The goals of WCAG are to:

• Make digital content work for everyone, no matter how they use and access the web.

• Offer clear, practical guidance that works across different devices, browsers, and tools.

• Keep accessibility guidelines up to date by learning from people with disabilities and the broader accessibility community.

Who is WCAG for?

WCAG guidelines apply to anyone who creates a digital experience — not just developers writing code. 

Designers use WCAG to make layouts, colors, and interactions easier to see and use. Developers rely on it to ensure websites and apps work smoothly for assistive technology users, including keyboard, screen reader, and other assistive device users. Content creators follow WCAG to write clear copy, structure pages logically, and make images, videos, and documents usable by more people.

From an organizational level, WCAG provides a clear set of guidelines that align teams around accessibility from the start. This ensures that teams across the organization are creating more accessible digital experiences and building products that work better for everyone — regardless of role, device, or ability.

"Principles and Guidelines" sits atop graphics depicting the 4 WCAG principles reading, "perceivable, operable, understandable, and robust."

How WCAG Works

WCAG accessibility guidelines are divided into four principles (known as the POUR principles), which help organizations apply accessibility guidelines more effectively. These principles include:

• Perceivable: Both information and user interface components must be presentable to users in ways they can perceive. For example, alt text should be provided for images so they can be understood by assistive technology users.

• 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. 

• Understandable: Information and the operation of the user interface must be understandable to a wide range of users. For example, web pages appear and operate in predictable ways.

• Robust: Content should be robust enough that it can be interpreted reliably by current and future user agents, including assistive technologies. 

Each of these principles includes various success criteria that explain what accessible digital content should do in practice. WCAG also defines three conformance levels: Level A, Level AA, and Level AAA. Level A addresses the most basic accessibility barriers, Level AA focuses on the most common challenges that affect the widest range of users, and Level AAA sets the highest accessibility standard. 

For most organizations, Level AA is the benchmark referenced by major laws and policies, including the Americans with Disabilities Act(opens in a new tab) (ADA) and Section 508.

WCAG Versions

The W3C has released multiple versions of the WCAG guidelines to keep accessibility aligned with evolving technologies and user needs. Today, the WCAG 2.x family is the most widely used framework for digital accessibility. 

WCAG 2.2, released in October 2023, introduced nine new success criteria focused on improving usability for people with cognitive and motor disabilities. These updates address everyday interactions like keeping focused elements visible, reducing reliance on dragging motions, increasing the size of clickable targets, and ensuring help options remain consistent across pages. 

Earlier versions laid the groundwork for these updates. WCAG 2.0 originally established 61 success criteria that defined the core principles of accessible digital content. WCAG 2.1, released in 2018, expanded on that foundation by adding 17 success criteria aimed at improving mobile accessibility, readability, and support for assistive technologies, such as screen readers and voice input. 

Each version of WCAG builds on the last, meaning WCAG 2.2 includes all requirements from WCAG 2.0 and 2.1 along with its newer additions. While work has begun on WCAG 3.0, it’s still in development and not expected to become a finalized standard for several years.

Is WCAG Required by Law?

While every organization should strive to provide the best possible experience to people with disabilities, WCAG 2.2 conformance is enforced in several accessibility laws, including the ADA and Section 508 of the Rehabilitation Act. While the European Accessibility Act(opens in a new tab) (EAA) enforces POUR principles, following the accessibility guidelines in WCAG 2.2 Level AA can help you meet EAA requirements.

Put simply: if you’re creating digital content — websites, mobile apps, web-delivered documents, user interfaces, or any other type of digital content — they must conform to WCAG 2.2 Level AA standards to be compliant with accessibility laws and regulations.

How WCAG Fits Into Website Accessibility

An important thing to note about WCAG: It’s only one piece of the bigger accessibility picture. At its core, accessibility is about creating digital experiences that people can actually use — across different abilities, devices, and ways of navigating the web. Rather than acting as a checklist to complete, WCAG provides guidance that supports better decisions across design, content, and development.

WCAG guidelines help teams think about accessibility at every stage, including:

• Design: Color contrast, readable fonts, clear layouts, and interaction patterns that don’t rely on one specific way of using a site.

• Content: Logical headings, descriptive links, text alternatives for images, and copy that’s easier to understand and navigate.

• Development: Keyboard-friendly interactions, visible focus indicators, predictable behavior, and compatibility with assistive technologies.

• Ongoing maintenance: Keeping accessibility in mind as content changes, features are added, and user needs evolve.

When accessibility is built into these areas from the start, WCAG becomes a reference point teams can return to — not a one-time requirement, but a framework that helps digital experiences work for everyone.