WCAG: Web Content Accessibility Guidelines Explained

Last Edited September 11, 2023 by Garenne Bigby in Accessibility Testing

wcag web content accessibility guideline

WCAG, which is short for Web Content Accessibility Guidelines, is a set of guidelines that are necessary for improving web accessibility. These guidelines are put together by the W3C (World Wide Web Consortium), and are the best way to make sure that your website is accessible to all of your users. This list is not an all-inclusive list of issues that web users with disabilities are faced with, but they are in fact recognized internationally and are the adopted standards. The guidelines are meant to explain how to solve a number of the problems that web users with disabilities are faced with.

WCAG 1.0

In 1999, the first version of the W3C's WCAG was put together, and this was an important milestone regarding web accessibility. In essence, it collaborated many years of vital knowledge of web developers around the world. This first version of the WCAG had only 14 guidelines and these were all divided up among 3 levels of priority. Priority level 1 was the most basic level of web accessibility. Priority level 2 was made to address the largest barriers for users with disabilities. Priority level 3 was made to ensure there were significant improvements among web accessibility.

WCAG 2.0

This is the current set of guidelines which have been in place since 2008 and should continue to be the standard for many years ahead. These guidelines are a bit more neutral regarding technology than the original outlined guidelines, which is what allows them to stay useful and relevant for much longer. The WCAG 2.0 was designed around principles, as opposed to technology, and the W3C put together an ethical statement along with useful guidance.

The 4 Principles of Accessibility

The 4 principles of the Web Content Accessibility Guidelines 2.0 are: perceivable, operable, understandable, and robust—or POUR which is easy enough to remember. The great thing about an approach like this with principles is that the emphasis is put on understanding the users. Yes it is great if you know what these guidelines are on paper, but it is vital for you to know why they exist as they do.

1. The Website Must Be Perceivable

This principle is based on the assumption that not every individual is using the same senses when browsing the internet. Some users might have a difficult time with one more even more of their senses. This makes them rely on assistive technologies when they are browsing the internet.

The 3 main senses that these guidelines are meant to help are weight, touch, and sound. While using the WCAG 2.0, you are working to make sure that individuals can perceive all of the content and information on the website.

2. The Website Must Be Operable

The idea of a website being operable is based on the actions that people take when they are browsing. This will cover a handful of ways that the user will browse the internet. Some individuals might have motor difficulties, meaning that they will use their keyboard to navigate, and some individuals will have impairments with their sight and will prefer to use their keyboard as opposed to their mouse.

The main issues for making a website operable are to ensure that there is good keyboard-only navigation that you avoid setting time limits for website users, and you should be helping the users if they happen to make any errors when filling out any form on your website.

3. The Website Must Be Understandable

Ensuring that a website is understandable is a bit different than the completion of the first two principles. A website that is perceivable and operable does not have any meaning if individuals are not able to understand it. The website should be using terms that are clear, should have instructions that are simple and explain the issues that are complex. You have to make sure that the website functions in a way that individuals will understand—by avoiding inconsistent, unexpected, or unusual functions.

4. The Website Must Be Robust

A website that is robust is one that can be relied on by third-party technology, like screen readers and web browsers. The website has to meet the recognized standards, like using clean CSS and HTML. This will minimize the risk of individuals using and relying on technologies that are not able to successfully process the website.

WCAG Levels

The WCAG 2.0 is organized into 3 levels of agreement.

  • Level A encompasses the most basic web accessibility features.
  • Level AA consists of the biggest and most prevalent barriers encountered by disabled users.
  • Level AAA deals with the highest and most involved level of web accessibility. 

For most websites on the internet, level AA and some level AAA is the target that needs to be hit. This is because some of the guidelines on the highest level simply are not able to be applied to all web sites. Nevertheless, one of the most common problems with this three tiered structure is that when people know that they are not able to reach level AAA, they will not give any thought to the guidelines to attempt improve on their accessibility using any guidelines on that level. It should be noted that it is vital to comply with as many of the guidelines as possible whether you are able to reach level AAA or not.

Starting at Level A is the ideal way to get on the path to progress and start helping out individuals that are visiting your website. Level AA is the standard that is being used by many governments as the benchmark, or target level, to address the most problematic and most common issues for web users with disabilities.

Web Content Accessibility Guidelines Evaluation

Yes, the World Wide Web Consortium's WCAG 2.0 is a huge step in the right direction for improving accessibility on the internet, there are still some unresolved issues. Mainly, they are virtually impossible to understand. Even those who are quite experienced in web development do sometimes fight to make sense of the guidelines that are riddled with hard to understand vernacular. The explanations given by the W3C uses terms and words that require separate definitions, some of which even have more specific definitions within them.

Despite the praise given for the WCAG 2.0's technologically objective and scrupulous approach. The guidelines give very little applicable instruction for web developers. Many of the guidelines are simple ideas akin to common sense, and when these are explained more clearly, they give benefits to users and developers alike.

More on Level A

This level complies with the simplest of guidelines set forth by the WCAG, and should be compliant by any website that aims to be used successfully by any individual. You should be:

  • Providing text alternatives for content that is non-text, providing alternatives to content that is audio-only or video-only, providing a second alternative for videos with audio, and providing captions for videos that have audio.
  • Ensuring that information and content has a logical structure, content is presented on a meaningful order, instructions should be able to be understood by more than one sense, and presentations should not rely only on one color.
  • Avoiding audio that plays automatically, avoiding keyboard-only accessibility, ensuring that keyboard users are not trapped, and users can control any time limits.
  • Ensuring that moving content can be controlled by users, ensure that content is not flashing more than 3 times per second as this can trigger seizures, and providing a link that will skip content.
  • Providing page titles that are clear and helpful, links should be clear given their context, and the page should have an assigned language.
  • Elements should not change when they have received focus or input, input errors should be clearly identifiable, give instructions and label elements, and make sure that there are no major errors in code.

More on Level AA

This level complies with the most common guidelines set forth by the WCAG, and should be used by those websites that aim to see the most success in their website's accessibility. This checklist encompasses items that do require a bit more thorough of an understanding of the WCAG, and is as follows:

  • Live videos should have captions, while there should be audio descriptions for video content. The contrast ratio between the background and the text should be at least 4.5:1 and text should be able to be resized up to 200% without losing content or function.
  • Images of text should not be used, and you should be offering several ways for users to be able to find pages. Always use clear labels and headings, while ensuring the keyboard focus is always clearly visible.
  • Indicate to users when the language on the page changes, consistently use icons, buttons, and menus.
  • Reduce the risk that users will encounter input errors for data that is sensitive, and suggest a fix when a user has made an error.

More on Level AAA

This level is made up of more intense accessibility guidelines that have been set forth by the WCAG. Not all websites can rise to this level, as it takes an invested understanding of the WCAG guidelines to successfully comply with all of the rules that are outlined:

  • Provide a sign language interpretation for all videos, provide a detailed description for all videos, and also provide a text alternative to all videos.
  • Ensure that the contrast ratio between the background and text is at least 7:1 and do not use images of text while do ensure that there are a wide range of presentations options available to the user.
  • Audio should be clear for all listeners to hear, and the page should be accessible by keyboard only if necessary, with no exceptions.
  • There should be no time limits given on any of the pages that would interrupt users when they are using the site.
  • User date should be saved when there is a need for re-authentication, and there should be no content that flashes more than 3 times per second so that seizures are not triggered.
  • Provide a way for users to know where they are, and the purpose of every link should be clear from the text provided. Break up text with headings, and if there are any strange words or abbreviations used, they should be explained after the first use.
  • The reading level should be so that users with 9 years of schooling will be able to read it, and any words that are hard to pronounce, should be explained.
  • Elements on your site should not be changed unless users have asked, and you should do all that you can to reduce the risk that there will be any input errors. This can be done by providing detailed instructions to help them. 

Overall, web accessibility is not as difficult as it may seem, and the long term benefits that it will have on your website are immense. Good web accessibility has the potential to keep a website legal and will save time and money. Web accessibility is a breeze when you are following the right path, and in reality all of the things that focus on helping website visitors with disabilities are things that will also be beneficial to all users. Once you have understood the WCAG, you will understand why it is important to make these changes.

The WCAG 2.0 can seem intimidating at first, but it should be noted that commonly, not all websites will reach level AAA of accessibility. At the very least, it is best to have all components of level AA with some components of level AAA. Not everyone has the means necessary to make their website level AAA compliant, but incorporating as much as possible is so much better than not trying to incorporate any of it at all. These guidelines explain how to solve a number of the problems that users face and are not only an adopted standard, but are internationally recognized as the solution to web accessibility.

Garenne Bigby
Author: Garenne BigbyWebsite:
Founder of DYNO Mapper and Former Advisory Committee Representative at the W3C.


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