What is involved in AAA WCAG conformance?

The Web Content Accessibility Guidelines (WCAG) are a set of criteria that measure different elements of a website. There are 78 success criteria across four sections that are separated into three levels of conformance: A, AA and AAA, where AAA is the highest level of accessibility.

In some cases, AAA conformance criteria are additional guidelines that have no direct connection to other criteria, however in other cases, AAA conformance criteria offer enhanced requirements for other A or AA level criteria. An example of this is text contrast: under AA conformance, standard size text must have a contrast ratio of at least 4.5:1. However under AAA conformance, this increases to 7:1.

Most of the organisations that come to Dig Inclusion ask for AA level conformance testing against the WCAG requirements. There are many reasons for this but AA level conformance is a good level of accessibility and the European Union has set as the level all public bodies must reach.

We often see requests from educational organisations who strive to be exemplars in their field and so wish to achieve the highest level of accessibility.

It may be the case that some organisations aiming for AA level may desire some AAA level criteria, such as a university having a number of students with a certain disability. Pursuing AAA criteria that directly enhances their experience, for example, language, may help the students when they visit the university’s website.

In order to obtain an AAA level of testing, all of the criteria under WCAG must be passed. Where AAA is not currently being achieved but is being worked toward this could be highlighted within the accessibility statement of the organisation.

There may be a belief that gaining an AAA level website is very difficult. This could be because of historical reasons, or a limit of resources dedicated to ongoing conformance for items such as sign language for multimedia. However it is not impossible and Dig Inclusion are able to work with you to obtain the level of accessibility best suited to your business and users.

Examples of AAA Success Criteria

Over a third of the WCAG success criteria are AAA level conformance, which shows WCAG’s commitment to the highest level of accessibility. The AAA success criteria are found within the Perceivable, Operable and Understandable sections of the guidelines.

In order to provide an overview of some of the criteria that are involved in AAA testing, we’ll look into each of these three sections. Rather than going through all the 28 criteria, below is a selection of AAA level criteria to help give an overview of the type of tests and considerations that web authors need in order to obtain a website with the highest level of accessibility.


Under the perceivable section of the guidelines, some of the AAA criteria cover enhanced provision for multimedia content. Specifically, this includes Sign Language provision and Extended Audio Description, where the media may pause the action in order to explain the context in detail. These can be turned on or off through options as they may not be suitable for all users.

Within the perceivable section we also find criteria for the visual display of information which supplements other existing criteria. The criterion Contrast (Enhanced) is an example, where text must have a contrast ratio of at least 7:1, and Image Text (No Exception), where there must be no image text present (logotypes are exempt).

The visual display of information also covers how any characters are permitted in the width of a block of text. The Visual Presentation criterion states that no more than 80 characters may be across the width of a page (40 for Chinese, Japanese or Korean characters). This is to help certain users who may struggle to perceive and read large amounts of text by having a limited number of characters in their field of view.


The operable criteria are about making sure that components and features of a website work in the expected and consistent manner. It is for this reason that we find criteria relating to keyboard only users, including the Keyboard (No Exception) criterion, where all functionality must be available for keyboard only users, with no exception.

There are also some criteria that are in place to allow a user to have access to a website, with the No Timing and No Interruptions criteria. Users are also able to extend their session to a website without losing data through the Re-authenticating and Timeouts criteria.

Additionally, there are some enhanced features to prevent people with photosensitive epilepsy and people with inner ear disorders while visiting web pages through the Three Flashes and Animation from Interactions criteria.

Another criterion to draw attention to is Target Size. In this criterion, the size of interactive objects is taken into consideration. Users with low dexterity, for example, may struggle to click on small targets. For this reason, targets, such as a submit button or a link, must be at least 44 x 44 CSS pixels. Exceptions are permitted, such as if there is an equivalent feature elsewhere on the page or if it is a link as part of text, but generally speaking, targets must be of a particular size.


The last section where AAA conformance criteria can be found are in the Understandable section. The largest group of these is in relation to words; namely Unusual Words, Abbreviations, Reading Level and Pronunciation.

Most of us will have times where we do not know a word or a whole page is written in very academic language. For some users, including those with cognitive disabilities, this is a particular hindrance and may result in them leaving a website altogether.

The criteria relating to words allows users to have mechanisms in place to help with understanding words, phrases or abbreviations without breaking up the flow of reading. The Reading Level of the website must not exceed a lower secondary education level. It is possible for a page to have a higher level reading ability as long as a second page is provided that does not exceed lower secondary education level.

Providing assistance is also important for some users. The Help and Error Prevention criteria are there to ensure that users have provision to prevent forms with errors being submitted unintentionally.

Testing under AAA

As with testing any website under A and AA conformance criteria, there are some tests that are quick and have a simple test that can give a clear pass or fail. An example of this is text contrast, where by using a tool and a couple of clicks we know where or not text has passed.

However some tests are more interpretative. An example of this is in relation to the lower secondary reading level. While there is some guidance and tools on understanding and fulfilling this criterion, the end result may require some discussion between team members to give a high level of confidence regarding the testing process.

In Conclusion

The WCAG Guidelines are categorised into three conformance levels, A, AA and AAA. To meet each level a website must meet all the guidelines of that level, plus those before. For example, for AA conformance you must meet A and AA guidelines, and for AAA you must meet AA conformance tests and the 28 additional AAA guidelines.

This totals 78 WCAG success criteria which must be passed for AAA conformance. If an organisation obtains an AA level, adding a few AAA criteria could enhance a user’s experience further. Even if you don’t aim for all of the AAA criteria we’d certainly recommend seeing what additional steps could be incorporated to continually improve the website.

Reaching level AAA conformance is not impossible, however there are some challenges and decisions that organisations must take. In taking these decisions and gaining a high level of accessibility, it allows all users to access, interpret and operate all areas of the website.

Aim for the highest standard

If you would like to know more about AAA conformance level testing, or would like us to conduct an audit of your website at any level, then please feel free to contact Dig Inclusion and speak to a member of our team.