Accessibility Standards Explorer

What are WCAG standards?

The Web Content Accessibility Guidelines (WCAG) are technical standards that make web content more accessible to people with disabilities. Developed by the W3C Web Accessibility Initiative (WAI), these guidelines are the global benchmark for digital accessibility.

WCAG is organised around four principles -Perceivable, Operable, Understandable, and Robust (POUR). Each principle contains guidelines, and each guideline has testable success criteria.

Understanding conformance levels

WCAG defines three levels of conformance:

Level AA is the most commonly targeted level, required by most accessibility laws including the Australian Disability Discrimination Act, European EN 301 549, and US Section 508.

WCAG version history

WCAG 2.0 (2008)

The original modern standard, still widely referenced. Established the four POUR principles and success criteria framework. Focused primarily on desktop web usage.

WCAG 2.1 (2018)

Added 17 new success criteria addressing:

• Mobile accessibility - Touch targets, device motion, orientation
• Low vision - Text spacing, reflow, non-text contrast
• Cognitive accessibility - Timeouts, animations, status messages

WCAG 2.2 (2023)

Added 9 new success criteria focusing on:

• Cognitive load - Consistent help, redundant entry, accessible authentication
• Mobile and touch - Dragging movements, target size minimums
• Focus appearance - Visible focus indicators

Key accessibility rules

Perceivable

Content must be presentable in ways users can perceive:

• Text alternatives - Images need alt text; complex images need long descriptions
• Captions and transcripts - Video needs captions; audio needs transcripts
• Adaptable content - Structure conveyed through markup, not just visual styling
• Distinguishable - Sufficient colour contrast; text resizable without loss

Operable

Interface must be operable by all users:

• Keyboard accessible - All functionality available via keyboard
• Enough time - Users can extend or disable time limits
• Seizure safe - No content flashes more than three times per second
• Navigable - Clear page titles, logical focus order, descriptive links

Understandable

Information and operation must be understandable:

• Readable - Language identified; unusual words explained
• Predictable - Consistent navigation; no unexpected context changes
• Input assistance - Clear labels; error identification and correction help

Robust

Content must be robust enough for assistive technologies:

• Compatible - Valid markup; name, role, value exposed to assistive tech
• Status messages - Important updates announced without focus change

Best practices vs standards

Best practices go beyond minimum requirements. They’re recommendations that improve usability for everyone, not just meeting compliance thresholds. Examples include:

• Providing skip navigation links
• Using descriptive link text instead of “click here”
• Ensuring logical reading order matches visual order
• Adding visible focus styles beyond browser defaults

Experimental rules test emerging techniques that may become future standards.

Common accessibility issues

The most frequent accessibility failures found in audits:

1. Missing or inadequate alt text - Images without alternatives
2. Low colour contrast - Text difficult to read against backgrounds
3. Missing form labels - Inputs not properly labelled
4. Missing page language - No lang attribute on HTML element
5. Empty links and buttons - Interactive elements without accessible names
6. Missing document structure - No headings or incorrect heading hierarchy

How this tool works

Select one or more accessibility standards to explore the rules that apply. Each rule includes a description, guidance on how to comply, and a link to detailed documentation from Deque’s axe accessibility engine. Use this to understand what automated testing covers and plan your accessibility compliance strategy.