WCAG 2.1 AA Requirements Explained: What You Need to Know

7 de mayo de 2026 · EAAPass Team wcag wcag 2.1 level aa accessibility standards web accessibility success criteria

Understanding WCAG 2.1 AA

The Web Content Accessibility Guidelines (WCAG) 2.1, published by the World Wide Web Consortium (W3C), are the internationally recognized standards for web accessibility. Level AA is the conformance level required by most accessibility laws worldwide, including the European Accessibility Act (EAA). But what exactly does WCAG 2.1 AA require? This guide breaks down every requirement in plain language.

How WCAG Is Structured

WCAG is organized into a clear hierarchy:

4 Principles: Perceivable, Operable, Understandable, Robust (POUR)
13 Guidelines: High-level goals within each principle
78 Success Criteria: Testable statements at three levels (A, AA, AAA)

Level AA conformance requires meeting all 30 Level A success criteria plus an additional 20 Level AA criteria, for a total of 50 success criteria. WCAG 2.1 added 17 new success criteria compared to WCAG 2.0, primarily addressing mobile accessibility, people with low vision, and people with cognitive and learning disabilities.

Principle 1: Perceivable

Content must be presentable in ways that all users can perceive.

1.1 Text Alternatives

1.1.1 Non-text Content (Level A): All non-text content (images, icons, charts, audio, video) must have a text alternative that serves the equivalent purpose. For decorative images, use empty alt attributes (alt=""). For complex images like charts, provide detailed descriptions.

1.2 Time-Based Media

1.2.1 Audio-only and Video-only (Level A): Provide text transcripts for audio-only content and either text descriptions or audio tracks for video-only content.

1.2.2 Captions (Level A): All pre-recorded audio in video content must have synchronized captions.

1.2.3 Audio Description or Alternative (Level A): Provide audio descriptions or text alternatives for video content where visual information is not conveyed through the audio track.

1.2.4 Captions Live (Level AA): Live audio content must have real-time captions.

1.2.5 Audio Description (Level AA): Pre-recorded video content must have audio descriptions for visual-only information.

1.3 Adaptable

1.3.1 Info and Relationships (Level A): Information, structure, and relationships conveyed visually must also be available programmatically. Use proper heading hierarchies, lists, tables, and form labels.

1.3.2 Meaningful Sequence (Level A): The reading order of content must be logical when the visual presentation is removed.

1.3.3 Sensory Characteristics (Level A): Instructions must not rely solely on sensory characteristics like shape, color, size, or visual location.

1.3.4 Orientation (Level AA, new in 2.1): Content must not be restricted to a single display orientation (portrait or landscape) unless a specific orientation is essential.

1.3.5 Identify Input Purpose (Level AA, new in 2.1): Input fields that collect personal information must have their purpose programmatically determinable using autocomplete attributes.

1.4 Distinguishable

1.4.1 Use of Color (Level A): Color must not be the only means of conveying information, indicating an action, or distinguishing visual elements.

1.4.2 Audio Control (Level A): If audio plays automatically for more than three seconds, provide a way to pause, stop, or control the volume.

1.4.3 Contrast Minimum (Level AA): Text must have a contrast ratio of at least 4.5:1 against its background. Large text (18pt or 14pt bold) requires a minimum of 3:1.

1.4.4 Resize Text (Level AA): Text must be resizable up to 200% without loss of content or functionality.

1.4.5 Images of Text (Level AA): Use real text instead of images of text, except for logos or situations where a particular visual presentation is essential.

1.4.10 Reflow (Level AA, new in 2.1): Content must reflow without requiring two-dimensional scrolling at 320 CSS pixels wide (for vertical scrolling content) or 256 CSS pixels high (for horizontal scrolling content).

1.4.11 Non-text Contrast (Level AA, new in 2.1): User interface components and graphical objects must have a contrast ratio of at least 3:1 against adjacent colors.

1.4.12 Text Spacing (Level AA, new in 2.1): No loss of content or functionality when users adjust line height, paragraph spacing, letter spacing, and word spacing.

1.4.13 Content on Hover or Focus (Level AA, new in 2.1): Content that appears on hover or focus must be dismissible, hoverable, and persistent.

Principle 2: Operable

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

2.1 Keyboard Accessible

2.1.1 Keyboard (Level A): All functionality must be operable through a keyboard interface without requiring specific timing for individual keystrokes.

2.1.2 No Keyboard Trap (Level A): If keyboard focus can be moved to a component, focus must be able to be moved away from that component using only the keyboard.

2.1.4 Character Key Shortcuts (Level A, new in 2.1): If single character key shortcuts exist, they must be able to be turned off, remapped, or only active when the component has focus.

2.2 Enough Time

2.2.1 Timing Adjustable (Level A): Users must be able to turn off, adjust, or extend time limits.

2.2.2 Pause, Stop, Hide (Level A): For auto-updating, moving, or blinking content, users must be able to pause, stop, or hide it.

2.3 Seizures and Physical Reactions

2.3.1 Three Flashes or Below Threshold (Level A): Content must not flash more than three times per second unless the flash is below the general flash and red flash thresholds.

2.4 Navigable

2.4.1 Bypass Blocks (Level A): Provide mechanisms to bypass blocks of content that are repeated on multiple pages, such as skip navigation links.

2.4.2 Page Titled (Level A): Web pages must have descriptive and informative titles.

2.4.3 Focus Order (Level A): Components must receive focus in a logical order that preserves meaning and operability.

2.4.4 Link Purpose (In Context) (Level A): The purpose of each link must be determinable from the link text or its context.

2.4.5 Multiple Ways (Level AA): Provide more than one way to locate a web page within a set of pages (e.g., navigation, search, site map).

2.4.6 Headings and Labels (Level AA): Headings and labels must describe topic or purpose.

2.4.7 Focus Visible (Level AA): Keyboard focus indicator must be visible.

2.5 Input Modalities (new in 2.1)

2.5.1 Pointer Gestures (Level A): Functionality operated through multipoint or path-based gestures must also be available through single-point activation.

2.5.2 Pointer Cancellation (Level A): Functionality triggered by single-pointer activation can be cancelled or undone.

2.5.3 Label in Name (Level A): For components with visible text labels, the accessible name must contain the visible text.

2.5.4 Motion Actuation (Level A): Functionality operated by device motion must also be available through user interface components, and motion response can be disabled.

Principle 3: Understandable

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

3.1 Readable

3.1.1 Language of Page (Level A): The default human language of each page must be programmatically determinable.

3.1.2 Language of Parts (Level AA): The human language of each passage or phrase that differs from the page language must be programmatically determinable.

3.2 Predictable

3.2.1 On Focus (Level A): Receiving focus on a component must not trigger a change of context.

3.2.2 On Input (Level A): Changing the setting of a user interface component must not automatically cause a change of context unless the user has been advised beforehand.

3.2.3 Consistent Navigation (Level AA): Navigation mechanisms repeated across multiple pages must appear in the same relative order each time.

3.2.4 Consistent Identification (Level AA): Components with the same functionality must be identified consistently across a set of pages.

3.3 Input Assistance

3.3.1 Error Identification (Level A): Input errors must be automatically detected and described to the user in text.

3.3.2 Labels or Instructions (Level A): Labels or instructions are provided when content requires user input.

3.3.3 Error Suggestion (Level AA): When input errors are detected and suggestions are known, provide the suggestions to the user.

3.3.4 Error Prevention - Legal, Financial, Data (Level AA): For pages that cause legal commitments or financial transactions, submissions must be reversible, verified, or confirmed.

Principle 4: Robust

Content must be robust enough to be interpreted by a variety of user agents, including assistive technologies.

4.1 Compatible

4.1.1 Parsing (Level A): In content implemented using markup languages, elements have complete start and end tags, are nested according to specifications, do not contain duplicate attributes, and IDs are unique. Note: this criterion was deprecated in WCAG 2.2 but remains in 2.1.

4.1.2 Name, Role, Value (Level A): For all user interface components, the name, role, and value must be programmatically determinable, and notification of changes must be available to user agents.

4.1.3 Status Messages (Level AA, new in 2.1): Status messages must be programmatically determinable through roles or properties so that they are presented to the user by assistive technologies without receiving focus.

How to Test for WCAG 2.1 AA Compliance

Testing requires a combination of automated and manual approaches:

Automated testing: Tools like EAAPass can automatically check many WCAG criteria across your entire website, identifying issues like missing alt text, insufficient contrast, and missing form labels.
Manual testing: Some criteria require human judgment, such as whether alt text is meaningful, whether content is understandable, and whether the focus order is logical.
Assistive technology testing: Test with screen readers (NVDA, JAWS, VoiceOver), keyboard-only navigation, and screen magnification tools.

Start Your WCAG 2.1 AA Compliance Journey

Meeting all 50 WCAG 2.1 AA success criteria may seem daunting, but with the right approach and tools, it is entirely achievable. Begin with an automated audit using EAAPass to understand your current compliance level, then systematically address each issue. Remember that accessibility is an ongoing commitment, not a one-time project.

Get your free WCAG 2.1 AA audit from EAAPass today and take the first step toward full compliance.