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What Is ISO/IEC 40500 for Web Accessibility?

Sep 29, 2023


Published by the International Standards Organization, (ISO) the ISO/IEC 40500 standard is identical to the Web Content Accessibility Guidelines (WCAG) 2.0. 

The two documents are exactly the same, word for word. Both explain a process for testing digital content (such as websites and mobile apps) for digital accessibility.

The only difference between ISO/IEC 40500 and WCAG 2.0 is that in some cases, ISO/IEC 40500:2012 compliance may be mandatory. Some countries rely on ISO technical standards, so codifying WCAG as an ISO standard may help to speed adoption of non-discrimination laws. 

Below, we’ll answer a few common questions about WCAG, the ISO, and digital accessibility.

What is WCAG 2.0, and why is it important?

WCAG 2.0 is a guidance document for achieving digital accessibility. It was published by the World Wide Web Consortium (W3C) in December 2008 and introduced significant changes to the earlier version of the guidelines (WCAG 1.0, which was officially released in May, 1999).

WCAG establishes four principles of accessibility: Content must be perceivable, operable, understandable, and robust. These four foundational principles can help webmasters create content that works for people with a range of abilities. 

WCAG 2.0 also includes testable statements called success criteria, which can be used to evaluate content for accessibility. While WCAG provides recommended techniques for meeting each success criterion, creators aren’t bound to those techniques — they can use any methods available to meet each requirement. 

Before WCAG 2.0, the internet didn’t have true technical standards for accessibility. Since its initial publication, WCAG 2.0 has become the basis of many non-discrimination laws.

Related: Is There a Legal Requirement to Implement WCAG?

Why is ISO/IEC 40500 exactly the same as WCAG 2.0?


WCAG is an international standard for a reason: It’s a simple, principle-based document that aims to improve experiences for a wide range of people with disabilities.

The ISO could create a completely new technical standard for digital accessibility, but that standard would probably have a great deal of overlap with WCAG. 

And WCAG 2.0 is well-established as a technical standard for legal compliance. The Rehabilitation Act of 1973 has been amended to explicitly require that organizations follow WCAG, and in the coming months, the Department of Justice is expected to issue a rule requiring WCAG conformance for institutions that must comply with Title II of the Americans with Disabilities Act (ADA).

Related: What to Know About the DOJ’s New Title II Web Accessibility Rules

Should I test my website against ISO/IEC 40500?

If you’re looking for ways to improve accessibility, the best practice is to test your content against the latest official version of WCAG. Currently, that’s WCAG 2.1, with WCAG 2.2 scheduled for publication in late 2023 or early 2024. 

Each new version of WCAG does not deprecate earlier standards. In other words, WCAG 2.0 is still important — and each of the success criteria from WCAG 2.0 appear word-for-word in WCAG 2.1 and 2.2 (with one potential exception, as WCAG 2.2 is expected to remove one criterion).

But by following the latest version of WCAG, you can ensure that your website works for a wide range of users. Even if you’re primarily concerned with ISO compliance, following a more recent version of WCAG can help you reach more people.

Related: Which WCAG Standards Do I Need to Follow?

Does the ISO provide a certification for web accessibility?

The ISO is an independent, non-governmental organization, and they don’t perform certifications — but many third-party organizations offer ISO compliance certification programs.

Many digital accessibility certifications are available, but most focus specifically on WCAG (not the identical ISO standard). For example, the AudioEye® Trusted Certification requires organizations to make a sincere commitment to substantial conformance with the latest version of WCAG.

WCAG does not require creators to claim conformance with any version of the guidelines. However, showcasing your commitment to accessibility can help people develop a positive image of your brand. 

Promoting your achievements can also help to start conversations about accessible design. By simply talking about WCAG, you’re helping the internet become a more welcoming place for people with disabilities.

But before considering certifications, you’ll need to test your content and fix accessibility barriers. Get started with a free automated website analysis, which compares content to the latest version of WCAG. For additional guidance, send us a message to connect with an expert. 

Use our free Website Accessibility Checker to scan your site for ADA and WCAG compliance.

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