What is web accessibility?

Web accessibility is about making web content that disabled people can use.

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What web accessibility means

Accessible web content is content that has been designed and developed to be easily consumed and interacted with by disabled people. It considers things like:

Fundamentally, web accessibility is about designing web content so that it doesn't present any barriers to disabled people accessing and using it. It supports social inclusion and increases the autonomy, privacy and personal development of disabled people.

For an overview of web accessibility, see this 4-minute video from the W3C, Video Introduction to Web Accessibility and W3C Standards.


On the web, accessibility is sometimes referred to by the numeronym ‘a11y’, often pronounced ‘A-eleven-Y’ or like the words ‘ally’ or ‘alley’. The numeral ‘11’ replaces the 11 letters between the first letter ‘a’ and the last letter ‘y’ of the word ‘accessibility’.

Choice of channels and input modes

Accessible websites work for people who use different senses — be they visual, auditory or tactile — to access information, ensuring that everyone gets the equivalent information, no matter which sense they use.

Accessible websites enable users to navigate and interact with the content using a variety of input modes, such as pointers, keyboards and voice. For these to work, it’s essential that web content has been marked up to be machine readable.

For more information, see the following Knowledge Areas:

Who is accessibility for?

Web accessibility is defined as a human right by the United Nations, which specifically references the rights of all people to have equal access to ‘information and communications technologies and systems’ in Article 9 of The Convention on the Rights of People with Disabilities (CRPD).

Worldwide, at least 1 billion people — 15% of the world’s population — have a recognised disability. For more details, see Disability Inclusion — The World Bank.

In the 2013 NZ Disability Survey, 24% of New Zealanders identified as disabled. Add to this the consideration that not everyone who is disabled self-identifies as being disabled, and the number is potentially higher. For more details, see Disability Survey: 2013 — Stats NZ.

Types of disabilities

Read the following information from the W3C’s Web Accessibility Initiative (WAI) about the different types of disabilities and the web accessibility barriers that people commonly experience:

Benefits of web accessibility to everyone

Web accessibility is essential for people with disabilities and useful for all.

World Wide Web Consortium

To learn about how designing for differences is useful to all, watch these videos from the W3C: Web Accessibility Perspectives — Explore the Impact and Benefits for Everyone.

From a business perspective, case studies show how digital accessibility:

For details, see The Business Case for Digital Accessibility — W3C.

Components of web accessibility

Web accessibility depends on websites, authoring tools and user agents, such as web browsers and assistive technologies, all working together. To learn more, see Essential Components of Web Accessibility — W3C.

Web accessibility standards

The international standards for web accessibility are published by the World Wide Web Consortium (W3C).

Created by the W3C’s international working group, Web Accessibility Initiative (WAI), the standards come in the form of guidelines and technical specifications that address the accessibility requirements for the essential components of web accessibility. For an overview of W3C’s suite of accessibility standards, see W3C Accessibility Standards Overview.

W3C is an international organisation founded in 1994 by the inventor of the Web, Tim Berners-Lee, with the aim of leading the web to its full potential. The W3C’s Web Accessibility Initiative (WAI) seeks to improve the quality of the web so that disabled people can easily use it. For more, see About W3C WAI — W3C.

The Web Content Accessibility Guidelines (WCAG)

WCAG applies to web content, that is, content that’s typically viewed in a web browser. To learn more about the guidelines, see these resources from the W3C:

POUR principles

The requirements in WCAG are organised under 4 key accessibility principles: Perceivable, Operable, Understandable, and Robust (POUR).

The POUR principles aim to ensure that people can perceive, navigate, interact with and understand web content using a variety of tools and technologies. See the W3C’s Understanding the 4 Principles of Accessibility.

For each POUR principle, W3C lists a number of accessibility considerations, and provides examples, technical specifications and user stories for each consideration.


User Agent Accessibility Guidelines (UAAG)

The UAAG guidelines apply to user agents to ensure that disabled people can use them. User agents include:

For more information, see the following resources from the W3C:

Authoring Tool Accessibility Guidelines (ATAG)

The ATAG guidelines apply to web content authoring tools, such as:

For more information, see these resources from the W3C:

Policies and legislation in New Zealand

In 2003, Cabinet directed NZ Government core agencies to meet the NZ Government Web Guidelines (now called ‘Web Standards’). For more, see Web Standards Cabinet Minute and Paper — Digital.govt.nz.

The Web Standards include the Web Accessibility Standard, which requires that web content meet the Web Content Accessibility Guidelines (WCAG) 2.1 at Level AA (subject to a few exceptions).

For a list of other relevant policies, see Legal and policy requirements for accessible websites — Digital.govt.nz.