Information and user interface components must be presentable to users in ways they can perceive.


  1. Text alternatives
  2. Time-based media
  3. Adaptable
  4. Distinguishable

1.1 Text alternatives

Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language.

1.1.1 Non-text content (Level A)

All non-text content that is presented to the user has a text alternative that serves the equivalent purpose.

I have written several articles on the subject of alt text. It is the first guideline and this is something that anyone can do, with a little bit of training and practice, to ensure their content is inclusive. Please follow the links below to access information, including how-to videos on how to write alt text.

In the WebAIM Million Survey Opens in new window, missing alt text has been the second most common error found in homepages for the last five years, though there has been a small improvement during that time. In the 2024 survey, 54.5% of homepages had missing alt text. In 2023, that figure was 58.2%. In 2019, that figure was 68%.

1.2 Time-based media

Provide alternatives for time-based media.

This covers audio and video content, which can be pre-recorded or live. There are two different issues that need to be considered here: video is usually visual content, and could therefore exclude people with sight impairments; audio could exclude people with hearing impairments. It is therefore important to provide captions, audio description or some alternative format, so that everybody can access your content.

This section is split into several subsections, as there are many combinations to consider. I have written blog posts on most of these, and included audio and video content which shows how you can adhere to the guidelines at both A and AA level.

1.2.1 Audio only and video only (Level A)

For prerecorded audio-only and prerecorded video-only media, the following are true, except when the audio or video is a media alternative for text and is clearly labelled as such:
  • Prerecorded Audio-only: An alternative for time-based media is provided that presents equivalent information for prerecorded audio-only content.
  • Prerecorded Video-only: Either an alternative for time-based media or an audio track is provided that presents equivalent information for prerecorded video-only content.

The following posts should help you with this criterion:

1.2.2 Captions (pre-recorded) (Level A)

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.

The following posts should help you with this criterion:

1.2.3 Audio description or media alternative (Level A)

An alternative for time-based media or audio description of the prerecorded video content is provided for synchronized media, except when the media is a media alternative for text and is clearly labeled as such.

There are several success criteria that overlap in this area. At A level, you can choose whether to provide an alternative (usually a transcript) or audio description. At AA level, audio description is required. At AAA, extended audio description and an alternative are required.

As this site is only dealing with conformance to AA level, we will look at alternative media as part of this success criterion, and audio description for success criterion 1.2.5 Audio Description.

1.2.4 Captions - live (Level AA)

Captions are provided for all live audio content in synchronized media.

Learn about Live Captions

1.2.5 Audio description (pre-recorded) (Level AA)

Audio description is provided for all prerecorded video content in synchronized media.

My blog post for this guideline is in two parts. Part 1Opens in new window covers the theory behind this and a description of how to achieve it. Part 2 Opens in new window shows a completed video with audio description.

1.3 Adaptable

Create content that can be presented in different ways (for example simpler layout) without losing information or structure.

This guideline contains success criteria that focus on making content and information available to users, no matter how they access it. Everything should be able to be perceived using a screen reader (audio or Braille) or magnification.

1.3.1 Info and relationships (Level A)

Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text.

When a sighted person looks at content, it is easy for them to spot headings, lists, tables and other visual formatting. They look different and they are used to make it easier to understand information. A blind or visually impaired person cannot access this information unless content has been created in a way that their screen reader can access. This means taking a little time to learn the correct ways of creating such content.

1.3.2 Meaningful sequence (Level A)

When the sequence in which content is presented affects its meaning, a correct reading sequence can be programmatically determined.

Although Word, and to a certain extent, html automatically read in a logical order, there are other commonly used applications that need programming to do this. Select from the list below:

1.3.3 Sensory characteristics (Level A)

Instructions provided for understanding and operating content do not rely solely on sensory characteristics of components such as shape, colour, size, visual location, orientation, or sound.

This guideline looks at instructions and information that rely purely on a particular sense. For example, if I asked you to click on a red circle to view my blog post, that could be tricky for someone with a visual impairment. So it is better to avoid that kind of thing.

Learn about sensory characteristics

1.3.4 Orientation (Level AA)

Content does not restrict its view and operation to a single display orientation, such as portrait or landscape, unless a specific display orientation is essential.

This is no less important than the other guidelines but it is rare that I see non-conformance with it.

Learn about orientation

1.3.5 Identify input purpose (Level AA)

The purpose of each input field collecting information about the user can be programmatically determined when:
  • The input field serves a purpose identified in the Input Purposes for User Interface Components section; and
  • The content is implemented using technologies with support for identifying the expected meaning for form input data.

This one is only really for people who use html and other web coding. It doesn't apply to forms in documents.

Learn how to code the input purpose

1.4 Distinguishable

Make it easier for users to see and hear content including separating foreground from background.

1.4.1 Use of colour (Level A)

Colour is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element.

Colour must not be used as the only visual means of conveying information. One of the places I see this the most is in Excel spreadsheets, where colour is use in pie charts and other visuals. It's okay to use colour but there must be a text alternative as well.

1.4.2 Audio control (Level A)

If any audio on a Web page plays automatically for more than 3 seconds, either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio volume independently from the overall system volume level.

This is largely taken care of now by Chromium browsers disabling the autoplay attribute, but just in case you were trying to find a way around that, learn about the audio control criterion.

1.4.3 Contrast (minimum) (Level AA)

The visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except for the following:
Large text
Large-scale text and images of large-scale text have a contrast ratio of at least 3:1.
Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement.
Text that is part of a logo or brand name has no contrast requirement.

Earlier, I mentioned some research that found 58.2% of WCAG fails were due to missing alt text. This was the second most common reason for failure. The most common reason, at 81% (2024), is poor colour contrast. You can learn more about colour contrast in the following posts:

1.4.4 Resize text (Level AA)

Except for captions and images of text, text can be resized without assistive technology up to 200 percent without loss of content or functionality.

Learn how to enable resizing of text

1.4.5 Images of text (Level AA)

If the technologies being used can achieve the visual presentation, text is used to convey information rather than images of text except for the following:
The image of text can be visually customized to the user's requirements
A particular presentation of text is essential to the information being conveyed.

Learn about images of text

1.4.10 Reflow (Level AA)

Content can be presented without loss of information or functionality, and without requiring scrolling in two dimensions for:
  • Vertical scrolling content at a width equivalent to 320 CSS pixels;
  • Horizontal scrolling content at a height equivalent to 256 CSS pixels.
Except for parts of the content which require two-dimensional layout for usage or meaning.

Learn how to achieve Reflow

1.4.11 Non-text contrast (Level AA)

The visual presentation of the following have a contrast ratio of at least 3:1 against adjacent colours.
  • User interface components
  • Graphical objects

This is an interesting criterion. Basically, anything that has colour and carries meaning, must have a minimum contrast of 3:1.

How to meet non-text contrast

1.4.12 Text spacing (Level AA)

In content implemented using markup languages that support the following text style properties, no loss of content or functionality occurs by setting all of the following and by changing no other style property:
  • Line height (line spacing) to at least 1.5 times the font size;
  • Spacing following paragraphs to at least 2 times the font size;
  • Letter spacing (tracking) to at least 0.12 times the font size;
  • Word spacing to at least 0.16 times the font size.

Word - Learn how to format text so that it is easier for people with a range of impairments to read.

1.4.13 Content on hover or focus (Level AA)

Where receiving and then removing pointer hover or keyboard focus triggers additional content to become visible and then hidden, the following are true:
A mechanism is available to dismiss the additional content without moving pointer hover or keyboard focus, unless the additional content communicates an input error or does not obscure or replace other content;
If pointer hover can trigger the additional content, then the pointer can be moved over the additional content without the additional content disappearing;
The additional content remains visible until the hover or focus trigger is removed, the user dismisses it, or its information is no longer valid.

This one turned out to be more complicated than I expected. I spent a long time playing with Javascript to write this post.

Learn how to code additional content that passes content on hover or focus.