WCAG 2.1 Compliance: Complete Technical Guide

Jurisdiction

Global (US, EU, Canada, Australia, UK, and most countries)

Who must comply

All websites with significant traffic or business importance. Required by ADA (US), European Accessibility Act (EU), Section 508 (US federal), and equivalent laws in 50+ countries.

Penalties

Legal requirement; failure triggers ADA/local law violations – Varies by jurisdiction; ADA violations $2,500-$75,000+; EU fines up to 4% of annual revenue

Perceivable: All content must be perceivable to users with disabilities

Includes 9 success criteria: alt text, captions, distinguishable content (contrast), color independence, audio descriptions, text alternatives, adaptability, etc.

Operable: All functionality must be operable via keyboard

Includes 9 success criteria: keyboard accessibility, no keyboard traps, focus visible, predictable navigation, input assistance, etc.

Understandable: All content must be understandable to users with cognitive disabilities

Includes 13 success criteria: readable language, predictable behavior, input assistance, error identification, spelling/grammar, etc.

Robust: Content must work with current and future assistive technologies

Includes 5 success criteria: valid HTML, proper semantic markup, ARIA usage, name/role/value for components, etc.

Level A: All 25 baseline success criteria met

Level AA: All Level A + 25 additional success criteria met (standard requirement)

Level AAA: All Level AA + Enhanced success criteria (optional for most, required by some organizations)

Alt text for all images (SC 1.1.1)

Captions for all pre-recorded audio/video (SC 1.2.1)

Audio descriptions for video (SC 1.2.3)

Color contrast 4.5:1 for text, 3:1 for large text (SC 1.4.3)

No reliance on color alone to convey information (SC 1.4.1)

Keyboard navigation enabled on all interactive elements (SC 2.1.1)

No keyboard traps (SC 2.1.2)

Visible focus indicators (SC 2.4.7)

Skip navigation links (SC 2.4.1)

Proper heading hierarchy (SC 1.3.1, 2.4.10)

Form labels and instructions clear (SC 1.3.1, 3.3.2)

Error identification and correction suggestions (SC 3.3.1, 3.3.4)

Language of page declared (SC 3.1.1)

No moving, scrolling, or auto-playing content without controls (SC 2.2.2)

Sufficient time to read and interact (SC 2.2.1)

No more than 3 flashes per second (SC 2.3.1)

Proper link text (SC 2.4.4)

ARIA used correctly for custom components (SC 4.1.2)

Mobile/zoom reflow at 200% zoom (SC 1.4.10)

Text spacing adjustable (SC 1.4.12)

Content reflow without horizontal scroll (SC 1.4.10)

WCAG 2.0 published; becomes international standard

WCAG 2.1 published; adds 17 new success criteria for mobile, low vision, and cognitive accessibility

WCAG 2.1 becomes official requirement in EU (EAA), US courts, Canada, Australia

WCAG 2.2 published (beta); adds 6 new success criteria

WCAG 3.0 (Silver) in development; major overhaul with outcome-based testing

WCAG 2.1 remains standard; 2.2 adoption increasing; 3.0 not yet mandatory