The Web Content Accessibility Guidelines, often abbreviated to WCAG, are a series of guidelines for improving web accessibility. Produced by the World Wide Web Consortium (W3C), the WCAG are the best means of making your website useful to all of your users.

Although they are not an all-inclusive list of issues facing web users with disabilities, they are internationally recognised and adopted standards. The guidelines explain how to solve many of the problems that your users with disabilities face.

Web Content Accessibility Guidelines 1.0

The W3C’s first incarnation of WCAG in 1999 was a huge leap in web accessibility, bringing together years of useful work by developers from across the world.

The Web Content Accessibility Guidelines 1.0 had 14 guidelines and divided them into 3 priority levels:

  • Priority 1 – the most basic level of web accessibility
  • Priority 2 – addressed the biggest barriers for users with disabilities
  • Priority 3 – significant improvements to web accessibility

Web Content Accessibility Guidelines 2.0

The current set of guidelines has been in force since 2008, and will run for many years yet. The guidelines are more technologically neutral than WCAG 1.0, allowing them to stay useful for longer.

By designing WCAG 2.0 around principles and not technology, the W3C created an ethical statement as well as useful guidance.

The principles of WCAG 2.0 are:
* Perceivable
* Operable
* Understandable
* Robust

You could say that a good website is a POUR website! (That joke works better on a screen reader, trust me.)

The beauty of a principled approach like POUR is the emphasis on understanding your users. Learning all the guidelines isn’t good enough if you don’t know why they exist.


The principle of a website being perceivable is all about the senses people use when browsing the web. Some of your users may have difficulties with one or more of their senses, making them reliant on assistive technology to browse your website.

The three main senses that the guidelines can help with are sight, sound and touch. With WCAG 2.0, you can make sure that users can perceive all the information on your website.


The principle of a website being operable is about the actions people take when browsing. This covers the different ways in which your users browse the web. Some of them may have motor difficulties, which means they use their keyboard to navigate and some users who have sight impairments often prefer to use a keyboard rather than a mouse too.

The main issues for making your website operable are, ensuring good keyboard-only navigation, avoiding setting time limits for your users and helping them out if they make errors on forms.


Making a website understandable is a different kind of task to the first two principles. A perceivable and operable website means nothing if your users can’t understand it.

Your website must use clear terms, have simple instructions and explain complex issues. You must also make your website function in a way that your users understand, by avoiding unusual, unexpected or inconsistent functions.


A robust website is one that third-party technology (like web browsers and screen readers) can rely on. Your website must meet recognised standards, such as using clean HTML and CSS. This minimises the risk of your users relying on technology that cannot correctly process your website.

WCAG 2.0 levels

The Web Content Accessibility Guidelines 2.0 are organised into three levels of conformance:

  • Level A – the most basic web accessibility features
  • Level AA – deals with the biggest and most common barriers for disabled users
  • Level AAA – the highest (and most complex) level of web accessibility

For most websites, Level AA plus some Level AAA is the best target. That’s because some of the highest level guidelines simply can’t be applied to all websites. However, one of the problems with the three-tier structure is that if people know they can’t attain AAA, they won’t even look through the guidelines to see where they can improve accessibility. With all of your projects, you should comply with all the guidelines you can, whether you want Level AAA or not.

Starting with Level A is a great way to make progress and begin helping out your users. Level AA is the standard many governments are using as a benchmark as this level targets the most common and most problematic issues for web users.

WCAG 2.0 evaluation

Although the W3C’s Web Content Accessibility Guidelines 2.0 are a huge step forward in improving web accessibility, they do have their issues. Primarily, they are almost impossible to understand.
Even experienced web developers sometimes struggle to make sense of the jargon-filled text of the guidelines. The W3C’s explanations use terms and words that need separate definitions, some of which have further definitions within them.

Despite my earlier praise for WCAG 2.0’s technologically neutral and principled approach, the guidelines offer little practical instruction for developers. The aim of this book is to begin to dispel the myth of complexity that the W3C have perpetuated. Most of the guidelines are common sense ideas that, when explained clearly, can benefit both developers and users.

Next steps

If you’d like to get started on a project of your own, it might be time to read my book, ‘How to Meet the Web Content Accessibility Guidleines 2.0‘ It covers all the guidelines and teaches you how to save time by building accessibility into projects from the start. You’ll also learn how to audit your existing websites and produce a plan of action for improving your accessibility.

Just want to browse the guidelines? Head on over and read articles about meeting all of the guidelines, arranged by compliance level.

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