WCAG Overview

Web Content Accessibility Guidelines (WCAG) is an international standard developed by the W3C to make web content accessible to people with disabilities.

What is WCAG?

WCAG provides a single shared standard for web content accessibility that meets the needs of individuals, organizations, and governments internationally. It explains how to make web content more accessible to people with disabilities including blindness and low vision, deafness and hearing loss, limited movement, speech disabilities, photosensitivity, and combinations of these, as well as some accommodation of learning disabilities and cognitive limitations.

Following WCAG guidelines makes content more usable to users in general, not just those with disabilities.

WCAG History

WCAG 1.0

May 1999

Legacy

The first version of WCAG, establishing 14 guidelines focused on making web content accessible.

Learn more about WCAG 1.0

WCAG 2.0

December 2008

ISO Standard

A major overhaul introducing the POUR principles and testable success criteria. Became ISO/IEC 40500:2012.

Learn more about WCAG 2.0

WCAG 2.1

June 2018

17 New Criteria

Added 17 new success criteria focusing on mobile accessibility, people with low vision, and people with cognitive and learning disabilities.

Learn more about WCAG 2.1

WCAG 2.2

October 2023

Current

Added 9 new success criteria and removed 1 (4.1.1 Parsing). Focus on mobile accessibility, cognitive disabilities, and low vision improvements.

Learn more about WCAG 2.2•See what's new

WCAG 3.0

In Development

Draft

The next generation of WCAG guidelines, currently in Working Draft stage with significant structural changes planned.

Learn more about WCAG 3.0

The POUR Principles

WCAG 2.2 is organized around four fundamental principles that form the foundation of web accessibility:

Perceivable

Information and user interface components must be presentable to users in ways they can perceive. This means users must be able to perceive the information being presented (it can't be invisible to all of their senses).

4 guidelines•29 success criteriaExplore

Operable

User interface components and navigation must be operable. This means users must be able to operate the interface (the interface cannot require interaction that a user cannot perform).

5 guidelines•29 success criteriaExplore

Understandable

Information and the operation of user interface must be understandable. This means users must be able to understand the information as well as the operation of the user interface.

3 guidelines•17 success criteriaExplore

Robust

Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies. This means users must be able to access the content as technologies advance.

1 guideline•2 success criteriaExplore

Conformance Levels

Each success criterion is assigned a level based on its impact on design and functionality:

Level AA

The minimum level of conformance. Must be satisfied for basic accessibility.

30 success criteria

Level AAAA

The standard level. Required for many laws and policies. Includes all Level A criteria plus additional requirements.

24 success criteria (plus all Level A)

Level AAAAAA

The highest level. Provides enhanced accessibility. May not be achievable for all content. Includes all Level A and AA criteria.

32 success criteria (plus all Level A and AA)

Legal Requirements

Many countries and jurisdictions have adopted WCAG as part of their accessibility laws:

Americans with Disabilities Act (ADA) - USA

Courts have interpreted the ADA to require WCAG 2.0 Level AA compliance for public and commercial websites.

Section 508 - USA Federal

Requires federal agencies to make their electronic content accessible. Updated in 2018 to align with WCAG 2.0 Level AA.

European Accessibility Act (EAA) - EU

Requires certain products and services to meet accessibility requirements based on WCAG 2.1 Level AA by June 2025.

EN 301 549 - EU Standard

European standard for digital accessibility that incorporates WCAG 2.1 Level AA requirements.

Ready to Get Started?

Explore the principles, check specific criteria, or jump into our learning resources.

Start with our Getting Started guide for a step-by-step introduction, or dive into specific principles and criteria that interest you.

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