WCAG 2.0: The International Standard for Web Accessibility and Inclusive Design

February 24, 2016 BY EMILY GRIFFIN
Updated: January 4, 2018

Aside from state and federal web accessibility laws, the most widely adopted and comprehensive technical standards have emerged not from a law, but from the W3C’s Web Content Accessibility Guidelines (WCAG).

The WCAG standard is the most detailed, up-to-date guideline for creating accessible web content. Although in the United States it is not yet backed by law, it has been voluntarily accepted and employed by numerous American educational institutions. It has also been referenced by laws in 14 countries and the EU.

Read on to learn why WCAG is rapidly emerging as the international standard of web accessibility.

What is the World Wide Web Consortium (W3C)?

WCAG was developed by the World Wide Web Consortium (W3C). Although their focus is not solely on accessibility, the W3C is widely regarded as the highest authority in web accessibility goals and universal design.

The consortium provides an online web development resource center that includes sample code implementations to demonstrate and encourage the use of standards, as well as prototypes and sample applications to illustrate new technology.

What is WCAG 2.0?

Published by W3C, the Web Content Accessibility Guidelines is a set of guidelines for making digital content accessible for all users, including those with disabilities.

WCAG is a set of guidelines for making content accessible for all users, including those with disabilities.

The WCAG standard:

  • Outlines best practices for making web content universally perceivable, operable, understandable, and robust.
  • Defines criteria for successful inclusive web design, with ascending levels of compliance (levels A, AA, and AAA).
  • Is composed and reviewed by a global community of digital experts.
  • Connects the world through common information technology and user experience standards.

What is the difference between the WCAG 1.0 and WCAG 2.0?

A preliminary version of WCAG was released in January, 1995, followed by WCAG 1.0 in 1999. WCAG 2.0 was released in December, 2008, and has emerged as the international standard in web accessibility.

WCAG 1.0 and WCAG 2.0 differ in the way they organize accessibility guidelines. WCAG 1.0 uses priority levels, whereas the WCAG 2.0 is oriented around four universal design principals.

WCAG 1.0

With WCAG 1.0, Priority 1 addresses criteria a web developer “must satisfy,” Priority 2 lists criteria a web developer “should satisfy,” and Priority 3 supplies optional checkpoints a web developer “may address.”

Because WCAG 1.0 was published in 1999, it primarily addresses HTML web pages, since that was the majority of web content at the time. It did could not account for advances in technology, new software, and advanced applications of digital content.

Worldwide, there are more than 750 million people with disabilities. As we move towards a highly connected world, it is critical that the Web be usable by anyone, regardless of individual capabilities and disabilities.

WCAG 2.0

WCAG 2.0’s essential design concepts are labeled perceivable, operable, understandable and robust.

While the WCAG 1.0 constructs levels of compliance, WCAG 2.0 asks that designers and developers meet all four of these principals for disabled users, and then select a degree of compliance (Level A, AA, or AAA).

  • Perceivable: Information and user interface components must be presentable to users in ways they can perceive. This means that users must be able to perceive the all relevant information in your content.
  • Operable: User interface components and navigation must be operable. This means that users must be able to operate the interface successfully.
  • Understandable: Information and the operation of user interface must be understandable. This means that users must be able to understand the information as well as the operation of the user interface.
  • Robust: Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies. Content must be accessible to all users, keeping up with advances in technology, such as mobile technology.

WCAG 2.0 Compliance: Level A vs. AA vs. AAA

WCAG 2.0 guideline outlines three levels of compliance. Level A is the highest priority and usually the easiest to achieve. Level AA is more comprehensive. Level AAA is the strictest, most comprehensive accessible design.

For example, compare the success criteria for accessible navigation.

  • Level A: (2.4.2) Web pages have titles that describe topic or purpose.
  • Level AA(2.4.5) More than one way is available to locate a Web page within a set of Web pages except where the Web Page is the result of, or a step in, a process.
  • Level AAA (2.4.10) Section headings are used to organize the content.

These all seem to be fairly common sense best practices for universal web design, and most web designers should be able to achieve Level AAA compliance for this.

Other facets of WCAG compliance levels are far more involved, whether they require more resources, coordination, or funds to meet. For instance, compare the WCAG compliance levels for accessible video and time-synced media:

  • Level A: (1.2.2) Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such.
  • Level AA: (1.2.4) In addition to Level A compliance, captions are provided for all live audio content in synchronized media.
  • Level AAA: (1.2.6) In addition to Levels A and AA compliance, sign language interpretation is provided for all prerecorded audio content in synchronized media.

WCAG 2.0 Level AA: a Happy Medium

WCAG documentation implies that meeting success criteria should not adversely impact the user experience. Since closed captions can be toggled on and off, they do not compromise the visual presentation. On the other hand, adding sign language interpretation might be more likely to impact the interface given the limitations of current video player technology.

To this end, the W3C is first to recognize that most organizations simply won’t be able to achieve Level AAA success, at least not right away.

In note 2 of the WCAG 2.0, W3C states:

“It is not recommended that Level AAA conformance be required as a general policy for entire sites because it is not possible to satisfy all Level AAA Success Criteria for some content.”

It is recommended, however, that web designers meet at least WCAG 2.0 Level A and aim for Level AA compliance.

Webmasters should heed this recommendation, since American disability law Section 508’s ICT refresh references WCAG 2.0 Level AA as the standard to shoot for. WCAG 2.0 Level AA is already best practice for government websites in the UK, Canada, New Zealand, and Australia.

WCAG 2.0 Standard at a Glance

  • Text Alternatives: Provide text alternatives for any non-text content so that it can be converted into other forms people need, such as large print, braille, speech, symbols, or simpler language. A text transcript is required for audio content.
  • Video Alternatives: Provide alternatives for video and audio. Closed captions and audio descriptions are required for time-synced video.
  • Adaptability: Create content that can be presented in different ways without losing information or structure.
  • Clarity: Make it easy for users to see and read content. Provide adequate color contrast and reduce visual clutter that affects legibility.
  • Keyboard Accessibility: Make all functionality available from a keyboard.
  • Time: Provide users enough time to read and use content.
  • Seizure Safety: Do not design content that might trigger a seizure for people with photosensitive epilepsy.
  • Navigability: Provide multiple, intuitive ways for users to navigate content.
  • Readability: Make text content easily readable and understandable, both visually and cognitively.
  • Predictability: Make pages appear and operate in predictable ways.
  • Input Assistance: Help users to avoid making mistakes; make corrections easy.
  • Compatibility: Maximize compatibility with across devices (desktop, tablet, mobile, Apple vs. PC, etc). Make sure content is compatible with assistive technologies (screen readers, sip/puff switches, etc).

Web Content Accessibility Checklist

Complete WCAG 2.0 Documentation

WCAG and Section 508

Section 508 of the Rehabilitation Act is the only US federal law that includes a technical standard on web accessibility. It preceded the creation of WCAG standards, which are substantially more complete and better adapted to modern web technology. For this reason, Section 508 will undergo an update to point to WCAG 2.0 Level AA standards for specific guidelines in the future.

Worldwide Web Accessibility Standards

While many disability laws lag behind in addressing digital access, WCAG 2.0 provides the most comprehensive web accessibility standard available today.

WCAG standards are not law in the United States, but many organizations use it as a guide for inclusive web design. Outside of the US, WCAG 2.0 has been directly referenced or adopted by 14 countries and the European Union.

The following table shows government accessibility standards and relevant legislation.

AustraliaWCAG 2.0 AADisability Discrimination ActAll government websites should comply with WCAG 2.0 AA by the end of 2014.
CanadaWCAG 2.0 AA

SGQRI 008 (based on WCAG 2.0)

Human Rights Act 1977

Ontarians with Disabilities Act (AODA)

Quebec: Standards sur l’accessibilité du Web

WCAG 1.0 compliance is required for all government websites. The Jodhan vs. Attorney General of Canada ruling requires the Canadian government to meet WCAG 2.0, which was implemented in 2011.

Ontario: AODA is required for all new Ontario government websites and existing websites by January 2016.

Quebec: Custom made standard based on WCAG 2.0 with specifics covering websites, downloadable documents and multimedia.

EUWCAG 1.0 AAEuropean Parliament Resolution (2002)Required for all EU commission websites. Progress towards WCAG 2.0 is being made by the Mandate M 376 working group, which started work in 2006.
FranceRGAA 3 (based on WCAG 2.0)Law No 2005-102, Article 47Updated in April 2015 to include best practices for HTML5 and ARIA. Required for all French government websites and French public websites (public services, municipal sites, public research, etc).
GermanyBITV 2 (based on WCAG 2.0)Federal Disabled Equalization LawBITV 2 was enacted in 2011, and is required for all government websites. It is based on WCAG 2.0.
Hong KongWCAG 2.0 AAWCAG 2.0 AA is the standard for government websites.
IndiaGuidelines for Indian Government Websites (based on WCAG 2.0 Level A)WCAG 2.0 Level A became the standard for Indian government websites in February 2009.
IrelandWCAG 2.0 AAThe Disability Act 2005Required for all government websites.
ItalyTechnical Rules of Law 4/2004 (based on WCAG 1.0 AA)Law No. 4/2004Required for all government websites.
JapanJIS X 8341 (based on WCAG 2.0)Required for all local and central government websites. Commercial websites are also encouraged to use it.
NetherlandsWCAG 2.0 AAGovernment websites must comply with the government web guidelines. There are no requirements for non-government websites.
New ZealandNew Zealand Government Web Standards 2.0 (WCAG 2.0 AA)Human Rights Amendment Act 2001Required for all government web sites.
NorwayWCAG 2.0 Level AALOV 2008-06-20 nr 42Requires all websites to be universally designed. Some exceptions to Level AA criteria are permitted regarding time-based media and social media.
SpainUNE 139803:2012 (based on WCAG 2.0 Level AA)Law 34/2002, Law 51/2003Required for all government websites. Not required for non-government websites.
United KingdomWCAG 2.0 Level AAEquality Act 2010Required for all UK government web sites. Other UK websites need to comply with the Equality Act and provide equal access, but this doesn’t specify technical standards.


USAWCAG 2.0 Level AASection 508 of Rehabilitation ActUS federal agencies’ websites must comply with Section 508 guidelines. Section 508 is undergoing an ICT refresh that “seeks to harmonize its requirements with various voluntary consensus standards, including the Web Accessibility Initiative’s Web Content Accessibility Guidelines (WCAG).”


So much of our modern life takes place online. It is not fair to make the web inaccessible to some.

This sentiment rings true with technology leaders around the globe who herald WCAG 2.0 as the prevalent standard in web accessibility. For so many countries, WCAG is literally law. For the United States, it’s only a matter of time before the WCAG standard has legal backing.

Accessibility aside, WCAG creates clearer communication through standardization. As such, agencies, institutions, and businesses should apply WCAG 2.0 principles if they want to stay current in the digital age.

This post was originally published on November 25, 2013 by Shannon Murphy as “WCAG 2.0: Emerging Standard for Web Accessibility and Video Captions,” and has been updated.

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