WCAG 2.1 Success Criteria
Complete reference for all Level A and AA success criteria. Each page includes descriptions, common violations, code examples, and step-by-step fixes.
50
Total Criteria
30
Level A (Minimum)
20
Level AA (Standard)
1. Perceivable
Information and UI components must be presentable in ways users can perceive.
Non-text Content
Provide text alternatives for images, icons, charts, and other non-text elements so assistive technologies can interpret them.
Audio-only and Video-only (Prerecorded)
Provide alternatives for prerecorded audio-only and video-only content. Audio needs a text transcript; video needs either a transcript or audio description.
Captions (Prerecorded)
Provide captions for all prerecorded audio content in synchronized media, except when the media is clearly labeled as an alternative for text.
Audio Description or Media Alternative (Prerecorded)
Provide audio description or a full text alternative for prerecorded video content in synchronized media.
Captions (Live)
Captions are provided for all live audio content in synchronized media, including live broadcasts, webinars, and streaming events.
Audio Description (Prerecorded)
Provide audio description for all prerecorded video content in synchronized media.
Info and Relationships
Information, structure, and relationships conveyed visually should also be available programmatically.
Meaningful Sequence
When the sequence of content affects meaning, the correct reading sequence can be programmatically determined.
Sensory Characteristics
Instructions for understanding and operating content should not rely solely on sensory characteristics like shape, color, size, visual location, orientation, or sound.
Orientation
Content should not restrict its view and operation to a single display orientation unless a specific orientation is essential.
Identify Input Purpose
The purpose of input fields collecting personal information can be programmatically determined when using standard autocomplete tokens.
Use of Color
Color should not be the only way to convey information, indicate an action, or distinguish elements.
Audio Control
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.
Contrast (Minimum)
Text and images of text must have sufficient contrast against their backgrounds.
Resize Text
Text should be resizable up to 200% without loss of content or functionality.
Images of Text
Avoid using images of text when the same presentation can be achieved with real text.
Reflow
Content should reflow to a single column at 320px width without requiring horizontal scrolling or losing information.
Non-text Contrast
User interface components and graphical objects must have sufficient contrast.
Text Spacing
No loss of content or functionality occurs when users override text spacing properties: line height to at least 1.5 times the font size, paragraph spacing to at least 2 times the font size, letter spacing to at least 0.12 times the font size, and word spacing to at least 0.16 times the font size.
Content on Hover or Focus
Where receiving and then removing pointer hover or keyboard focus triggers additional content to become visible and then hidden, the additional content is dismissable without moving focus, hoverable so the user can move the pointer over it, and persistent until dismissed or no longer valid.
2. Operable
UI components and navigation must be operable by all users.
Keyboard
All functionality must be operable through a keyboard interface.
No Keyboard Trap
Users must be able to navigate away from any component using only the keyboard.
Character Key Shortcuts
If a keyboard shortcut is implemented using only letter, punctuation, number, or symbol characters, then at least one of the following is true: the shortcut can be turned off, remapped to include a modifier key (Ctrl, Alt), or is only active when the relevant component has focus.
Timing Adjustable
For time limits set by content, users must be able to turn off, adjust, or extend the time.
Pause, Stop, Hide
For moving, blinking, scrolling, or auto-updating content, users must be able to pause, stop, or hide it.
Three Flashes or Below Threshold
Web pages do not contain anything that flashes more than three times in any one-second period, or the flash is below the general flash and red flash thresholds.
Bypass Blocks
Provide a mechanism to bypass repeated content like navigation.
Page Titled
Web pages must have descriptive and unique titles.
Focus Order
Focus should move through content in a logical order that preserves meaning.
Link Purpose (In Context)
The purpose of each link should be clear from its text or surrounding context.
Multiple Ways
Provide more than one way to locate a web page within a set of pages, except when the page is a step in a process.
Headings and Labels
Headings and labels should describe topic or purpose clearly.
Focus Visible
Any keyboard-operable user interface must have a visible focus indicator.
Pointer Gestures
All functionality that uses multipoint or path-based gestures for operation can be operated with a single pointer without a path-based gesture, unless a multipoint or path-based gesture is essential.
Pointer Cancellation
For functionality that can be operated using a single pointer, at least one of the following is true: the down-event is not used to execute the function, the function completes on the up-event with the ability to abort or undo, the up-event reverses the outcome of the down-event, or completing the function on the down-event is essential.
Label in Name
The accessible name of UI components should contain the visible label text.
Motion Actuation
Functionality that can be operated by device motion or user motion can also be operated by user interface components, and responding to the motion can be disabled to prevent accidental actuation, unless the motion is essential or disabling would invalidate the activity.
3. Understandable
Information and the operation of the UI must be understandable.
Language of Page
The default human language of each page must be programmatically identified.
Language of Parts
Identify the language of passages or phrases that differ from the page language.
On Focus
When a component receives focus, it should not trigger a change of context automatically.
On Input
Changing a form control's value should not automatically cause a change of context unless the user is warned beforehand.
Consistent Navigation
Navigation mechanisms that appear on multiple pages should be presented in the same relative order each time.
Consistent Identification
Components that have the same functionality within a set of web pages are identified consistently. Icons, labels, and text alternatives for equivalent functions must match across pages.
Error Identification
When an input error is detected, the error must be identified and described to the user in text.
Labels or Instructions
Provide clear labels or instructions when user input is required.
Error Suggestion
If an input error is automatically detected and suggestions for correction are known, then the suggestions are provided to the user, unless it would jeopardize the security or purpose of the content.
Error Prevention (Legal, Financial, Data)
For web pages that cause legal commitments or financial transactions, that modify or delete user-controllable data, or that submit test responses, at least one of the following is true: submissions are reversible, data is checked for errors and the user can correct them, or a mechanism is available to review, confirm, and correct before finalizing.
4. Robust
Content must be robust enough to be interpreted by a wide variety of user agents.
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