Non-text Content
Tier 1 · The normative floor
Baseline compliance
What the normative text of WCAG 2.2 requires, and nothing more. Only a failure of this tier is a WCAG failure.
The bare minimum
Every piece of non-text content shown to users has a text alternative that serves the equivalent purpose. Controls and inputs need a name that describes their purpose. Time-based media, tests that would be invalid in text, and content meant to create a specific sensory experience only need a text alternative that identifies them. A CAPTCHA needs a text alternative describing its purpose and a version that uses a different sense. Content that is pure decoration, used only for visual formatting, or not presented to users must be implemented so assistive technology can ignore it.
Normative text
Verbatim from WCAG 2.2, W3C Recommendation 12 December 2024. Underlined terms are defined below.
All non-text content that is presented to the user has a text alternative that serves the equivalent purpose, except for the situations listed below.
- Controls, Input
- If non-text content is a control or accepts user input, then it has a name that describes its purpose. (Refer to Success Criterion 4.1.2 for additional requirements for controls and content that accepts user input.)
- Time-Based Media
- If non-text content is time-based media, then text alternatives at least provide descriptive identification of the non-text content. (Refer to Guideline 1.2 for additional requirements for media.)
- Test
- If non-text content is a test or exercise that would be invalid if presented in text, then text alternatives at least provide descriptive identification of the non-text content.
- Sensory
- If non-text content is primarily intended to create a specific sensory experience, then text alternatives at least provide descriptive identification of the non-text content.
- CAPTCHA
- If the purpose of non-text content is to confirm that content is being accessed by a person rather than a computer, then text alternatives that identify and describe the purpose of the non-text content are provided, and alternative forms of CAPTCHA using output modes for different types of sensory perception are provided to accommodate different disabilities.
- Decoration, Formatting, Invisible
- If non-text content is pure decoration, is used only for visual formatting, or is not presented to users, then it is implemented in a way that it can be ignored by assistive technology.
Known failures
These fail this criterion or a related one named in the text. Log them as WCAG failures.
- A chart whose alt text only names it ("Sales chart") without conveying what it shows doesn't serve the equivalent purpose.
Not required by the normative text
Common claims that this criterion does not support. Don't log these as WCAG failures.
- A particular length or wording for alt text. The test is equivalent purpose, not a character count.
- The alt attribute specifically. A text alternative is any text programmatically associated with the content, or referred to from text that is.
- Describing every visual detail. Only the image's purpose has to be served.
Definitions used (8)
Glossary definitions are normative. Their notes are informative.
- non-text content
-
any content that is not a sequence of characters that can be programmatically determined or where the sequence is not expressing something in human language
Informative notes (1)
This includes ASCII art (which is a pattern of characters), emoticons, leetspeak (which uses character substitution), and images representing text
- text alternative
-
Text that is programmatically associated with non-text content or referred to from text that is programmatically associated with non-text content. Programmatically associated text is text whose location can be programmatically determined from the non-text content.
Informative notes (1)
Refer to Understanding Text Alternatives for more information.
- name
-
text by which software can identify a component within web content to the user
Informative notes (2)
The name may be hidden and only exposed by assistive technology, whereas a label is presented to all users. In many (but not all) cases, the label and the name are the same.
This is unrelated to the name attribute in HTML.
- text
-
sequence of characters that can be programmatically determined, where the sequence is expressing something in human language
- specific sensory experience
-
a sensory experience that is not purely decorative and does not primarily convey important information or perform a function
- CAPTCHA
-
initialism for "Completely Automated Public Turing test to tell Computers and Humans Apart"
Informative notes (2)
CAPTCHA tests often involve asking the user to type in text that is displayed in an obscured image or audio file.
A Turing test is any system of tests designed to differentiate a human from a computer. It is named after famed computer scientist Alan Turing. The term was coined by researchers at Carnegie Mellon University.
- pure decoration
-
serving only an aesthetic purpose, providing no information, and having no functionality
Informative notes (1)
Text is only purely decorative if the words can be rearranged or substituted without changing their purpose.
- assistive technology
-
hardware and/or software that acts as a user agent, or along with a mainstream user agent, to provide functionality to meet the requirements of users with disabilities that go beyond those offered by mainstream user agents
Informative notes (3)
Functionality provided by assistive technology includes alternative presentations (e.g., as synthesized speech or magnified content), alternative input methods (e.g., voice), additional navigation or orientation mechanisms, and content transformations (e.g., to make tables more accessible).
Assistive technologies often communicate data and messages with mainstream user agents by using and monitoring APIs.
The distinction between mainstream user agents and assistive technologies is not absolute. Many mainstream user agents provide some features to assist individuals with disabilities. The basic difference is that mainstream user agents target broad and diverse audiences that usually include people with and without disabilities. Assistive technologies target narrowly defined populations of users with specific disabilities. The assistance provided by an assistive technology is more specific and appropriate to the needs of its target users. The mainstream user agent may provide important functionality to assistive technologies like retrieving web content from program objects or parsing markup into identifiable bundles.
Tier 2 · The gap
Usability & user impact
Where content can meet this criterion and still make things harder for people with disabilities. These are not failures of SC 1.1.1, so raise them as usability defects. Known failures, including failures of related criteria, are listed in Tier 1.
Alt text can be present and equivalent yet still tiring to use, for example when it repeats the caption beside it or runs to a paragraph.
Tier 3 · The golden path
Recommended best practice
The pattern that meets the floor, closes the gap, and avoids audit disputes. A recommendation, not a requirement.
Write alt text for the image's purpose in its context, as if replacing the image with words. Keep it short. Give charts and diagrams a brief alt plus a full description or data table nearby. Make the alt field required in your CMS, with an explicit "decorative" option.
W3C's Understanding document and techniques for SC 1.1.1 ↗ are informative: sufficient techniques show ways to pass, and documented failures show common ways to fail, but neither changes what the criterion requires.
How SC 1.1.1 maps to the WCAG 3 draft
From this site's reviewed map to the WCAG 3 editor's draft. It's an interpretation: W3C has not published a mapping.
Successor provisions
Related, not a successor
From WCAG 2.2, section 5.1: “The main content of WCAG 2.2 is normative and defines requirements that impact conformance claims. Introductory material, appendices, sections marked as "non-normative", diagrams, examples, and notes are informative (non-normative). Non-normative material provides advisory information to help interpret the guidelines but does not create requirements that impact a conformance claim.”