WCAG = Web Content Accessibility Guidelines
2.1 = Version 2.1, published June 2018
AA = Level Double-A, the middle conformance level
WCAG is developed by the W3C (World Wide Web Consortium) — the same organization that defines HTML and CSS standards. Version 2.1 added 17 new criteria on top of WCAG 2.0, primarily addressing mobile accessibility and cognitive disabilities.
See how 321 websites scored →
View the 2026 Report| Level | Criteria Count | Requirement | Legal Standard? |
|---|---|---|---|
| A Single-A | 30 | Minimum baseline. Missing these creates severe barriers. | Rarely sufficient alone |
| AA Double-A | 50 (A + AA) | The widely accepted legal and industry standard. | Yes — US, EU, UK, AU |
| AAA Triple-A | 78 (A + AA + AAA) | Enhanced accessibility, not achievable for all content types. | Not required by most laws |
When someone says "WCAG compliant" for legal purposes, they almost always mean WCAG 2.1 Level AA. Full AA conformance requires meeting all 30 Level A and all 20 Level AA criteria.
All WCAG criteria fall under four principles, collectively known as POUR:
Information and UI components must be presentable to users in ways they can perceive. You cannot present content only in one sensory modality — not everyone can see, hear, or feel it.
Examples: alt text for images, captions for video, enough color contrast, content that reflows without horizontal scrolling.
UI components and navigation must be operable. Users must be able to interact with everything using more than just a mouse — keyboard, switch access, voice control.
Examples: keyboard access to all functionality, no content that causes seizures, sufficient time to complete tasks, skip navigation links.
Information and UI operation must be understandable. Content must be readable, predictable, and help users avoid and correct mistakes.
Examples: page language declared in HTML, consistent navigation, helpful error messages on forms, autocomplete on common input types.
Content must be robust enough to be interpreted reliably by a wide variety of user agents, including current and future assistive technologies.
Examples: valid HTML, correct ARIA usage, status messages announced to screen readers.
These 17 criteria were added in WCAG 2.1 (not in 2.0) and are commonly missed:
| Criterion | Level | What It Requires |
|---|---|---|
| 1.3.4 Orientation | AA | Don't lock the page to portrait or landscape orientation |
| 1.3.5 Identify Input Purpose | AA | Use HTML autocomplete attributes on personal data fields |
| 1.4.10 Reflow | AA | Content reflows at 320px width with no horizontal scroll |
| 1.4.11 Non-text Contrast | AA | UI components and focus indicators need 3:1 contrast |
| 1.4.12 Text Spacing | AA | Content works when text spacing is increased via CSS |
| 1.4.13 Content on Hover or Focus | AA | Tooltips/dropdowns triggered on hover must be dismissable and hoverable |
| 2.1.4 Character Key Shortcuts | A | Single-key shortcuts must be remappable or disableable |
| 2.5.1 Pointer Gestures | A | All multipoint gestures (pinch, swipe) need single-pointer alternatives |
| 4.1.3 Status Messages | AA | Dynamic status updates must be announced to screen readers via ARIA live regions |
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