WCAG: Web Content Accessibility Guidelines

The Web Content Accessibility Guidelines (WCAG) are the international standard for the accessibility of web content. They were developedby the Web Accessibility Initiative (WAI) of the World Wide Web Consortium (W3C) to ensure that digital content and access to technology are equally available to all people, regardless of their disabilities or technical limitations.

A guideline for the accessibility of web content

The WCAG are of central importance in web development. They provide clear guidance for creating websites that are accessible to all people, including those with visual impairments, hearing problems, motor impairments or cognitive and learning disabilities. The WCAG play a decisive role in the Ordinance on the Creation of Accessible Information Technology under the Disability Equality Act (BITV for short). In this article, we explain the WCAG, its principles, versions and the associated success criteria in detail.

What are the WCAG?

The Web Content Accessibility Guidelines (WCAG) are a set of guidelines for creating conformity for greater accessibility in the digital space. These guidelines include techniques such as the comprehensibility and visibility of text, assistive tools such as screen readers, instructions for improved navigation and the like.

Important points:

• The WCAG provides a global standard for web accessibility.

• They are divided into three conformance levels (A, AA, AAA), which have different accessibility requirements.

• The guidelines cover four main principles: Perceivability, Usability, Understandability and Robustness.

  The four principles of WCAG

  The following four main principles of WCAG form the basis for the development of accessible websites and user agents.

  Perceivable

The principle of perceivability means that information and user interfaces must be presented in such a way that they can be perceived by all users.

Examples of success criteria:

• Text alternatives for images and multimedia content.

• Contrast ratios between text and background.

• Subtitles for videos and audio descriptions.

Operable

The principle of operability ensures that user interfaces and navigation elements can be used by all people, regardless of the technologies used.

Examples of success criteria:

• The website must be fully operable using a keyboard.

• No content must trigger seizures (e.g. due to flickering lights).

• Navigation must be logical and intuitive.

Understandable

The principle of comprehensibility means that information and the operation of the user interface are easy to understand.

Examples of success criteria:

• The language of the page must be clearly defined in context.

• Navigation should be consistent and predictable.

• Error messages should be understandable and helpful.

Robust (Robust)

The principle of robustness states that content must be designed to be compatible with a variety of user agents, including assistive technologies.

Examples of success criteria:

• Content must be compatible with screen readers and other assistive technologies.

• The website must work on different browsers and devices.

WCAG versions: WCAG 2.0, 2.1 and 2.2

The World Wide Web Consortium has continuously developed the WCAG over the years to keep pace with rapid technological advances.

WCAG 2.0

WCAG 2.0 was published in 2008 and quickly established itself as the global standard for web accessibility. It consists of 12 guidelines organized into the four principles mentioned above.

WCAG 2.1

WCAG 2.1 was published in 2018 with the aim of expanding the guidelines to include requirements for mobile accessibility, people with cognitive disabilities and other groups. WCAG 2.1 is fully backwards compatible with WCAG 2.0.

WCAG 2.2

WCAG 2.2 was published in 2023 and added a further nine success criteria to address new technologies and user requirements. Importantly, WCAG 2.2 is also backwards compatible and therefore also fulfills the requirements of previous versions.

Success criteria and conformance levels in the WCAG

The WCAG define success criteria that websites must meet in order to be considered accessible. These success criteria are divided into three conformance levels:

Conformance Level A

Level A comprises the most basic requirements. These criteria must be met for a website to be considered accessible at all.

Example:

All images must have alternative text.

Conformity level AA

Level AA contains stricter requirements that are often prescribed by law.

Example:

The contrast ratio between text and background must be at least 4.5:1.

Conformity level AAA

Level AAA sets the highest requirements for accessibility. These criteria are often desirable, but not always required by law.

Example:

Text should be available in multiple languages, and Plain Language or Easy Language options should be provided.

The future of WCAG and web accessibility

WCAG is constantly evolving to keep pace with advances in web technology. The next generation, WCAG 3.0, is expected to introduce more comprehensive requirements and a new success criterion that is even more responsive to individual needs.

Further information

Website of the WAI (Web Accessibility Initiative)

Web Content Accessibility Guidelines 2.2

Ordinance on the creation of barrier-free information technology in accordance with the Disability Discrimination Act