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WCAG 2.1 Success Criteria Reference

The 20 most important WCAG 2.1 success criteria with testing instructions, code examples, and common failures.

Level A: 14 Level AA: 6

Perceivable

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

1.1.1
Non-text Content All non-text content (images, icons, charts, CAPTCHA) must have a text alternative that serves the e...
A 1.3.1
Info and Relationships Information, structure, and relationships conveyed through presentation (visual layout) must also be...
A 1.4.1
Use of Color Color must not be the only visual means of conveying information, indicating an action, prompting a ...
A 1.4.3
Contrast (Minimum) Text and images of text must have a contrast ratio of at least 4.5:1 against their background. Large...
AA 1.4.4
Resize Text Text must be resizable up to 200% without assistive technology and without loss of content or functi...
AA 1.4.11
Non-text Contrast UI components (form inputs, buttons, focus indicators) and meaningful graphical objects must have at...
AA

Operable

User interface components and navigation must be operable by all users.

2.1.1
Keyboard All functionality must be operable through a keyboard interface without requiring specific timing fo...
A 2.1.2
No Keyboard Trap If keyboard focus can be moved to a component, focus must be able to be moved away using only a keyb...
A 2.4.1
Bypass Blocks A mechanism must be available to bypass blocks of content that are repeated on multiple pages, such ...
A 2.4.2
Page Titled Web pages must have titles that describe their topic or purpose. The title element appears in the br...
A 2.4.4
Link Purpose (In Context) The purpose of each link must be determinable from the link text alone, or from the link text togeth...
A 2.4.6
Headings and Labels Headings and labels must describe the topic or purpose of the content they introduce. Clear headings...
AA 2.4.7
Focus Visible Any keyboard-operable user interface must have a visible focus indicator. Users navigating with a ke...
AA

Understandable

Information and the operation of the user interface must be understandable.

3.1.1
Language of Page The default human language of each web page must be programmatically identified using the lang attri...
A 3.2.1
On Focus When a UI component receives focus, it must not initiate a change of context. Users should be able t...
A 3.3.1
Error Identification If an input error is automatically detected, the item that is in error must be identified and the er...
A 3.3.2
Labels or Instructions Labels or instructions must be provided when content requires user input. Every form field needs a v...
A

Robust

Content must be robust enough to be interpreted by a wide variety of assistive technologies.

4.1.1
Parsing Content must be implemented using well-formed HTML. While modern browsers are forgiving, malformed m...
A 4.1.2
Name, Role, Value For all UI components, the name (accessible label), role (what type of element it is), and value/sta...
A 4.1.3
Status Messages Status messages that provide information about success, progress, or errors must be programmatically...
AA