The complete WCAG 2.1 Level A & AA checklist.

The Web Content Accessibility Guidelines (WCAG) 2.1, published by the W3C in June 2018, is the current de-facto accessibility standard cited in US ADA case law, the EU's European Accessibility Act, and Section 508 (US federal procurement). WCAG 2.2 (October 2023) is a superset; conforming to 2.1 AA gets you most of the way to 2.2 AA.

WCAG defines three conformance levels:

• Level A — minimum, basic accessibility. 30 criteria in WCAG 2.1.
• Level AA — addresses major barriers. 20 additional criteria. This is the level cited in nearly every US legal context (ADA Title II 2024 rule, Title III settlements, Section 508 Refresh).
• Level AAA — the highest conformance level. Not required for general conformance; some criteria are infeasible for all content.

This checklist focuses on Level A + AA, the 50 criteria most teams need to verify.

Information and UI components must be presentable in ways users can perceive.

1.1 Text alternatives

• 1.1.1 Non-text Content (A) — Every non-text element (images, icons, charts) has a text alternative. Decorative images use alt=""; informative images describe the content; functional images describe the action.

1.2 Time-based media

• 1.2.1 Audio-only and Video-only (Prerecorded) (A) — Transcript for audio; transcript or audio-description for video.
• 1.2.2 Captions (Prerecorded) (A) — Captions for all prerecorded audio in synced media.
• 1.2.3 Audio Description or Media Alternative (Prerecorded) (A) — Audio description or full media alternative for prerecorded video.
• 1.2.4 Captions (Live) (AA) — Captions for live audio.
• 1.2.5 Audio Description (Prerecorded) (AA) — Audio description for prerecorded video.

1.3 Adaptable

• 1.3.1 Info and Relationships (A) — Structure conveyed visually is programmatically determinable. Headings use <h1>-<h6>; lists use <ul>/<ol>; tables use <th> with scope.
• 1.3.2 Meaningful Sequence (A) — Reading order is programmatically determinable.
• 1.3.3 Sensory Characteristics (A) — Instructions don't rely solely on shape, color, size, or position.
• 1.3.4 Orientation (AA) — Content works in portrait and landscape.
• 1.3.5 Identify Input Purpose (AA) — Form fields use autocomplete for known input purposes (name, email, address).

1.4 Distinguishable

• 1.4.1 Use of Color (A) — Color is not the only means of conveying information.
• 1.4.2 Audio Control (A) — Auto-playing audio > 3s has a pause/stop/volume control.
• 1.4.3 Contrast (Minimum) (AA) — Text contrast ratio 4.5:1 (3:1 for large text 18pt+ or 14pt bold+). The most common WCAG failure.
• 1.4.4 Resize Text (AA) — Text can be resized up to 200% without loss of content or function.
• 1.4.5 Images of Text (AA) — Use text instead of images of text, except for logos.
• 1.4.10 Reflow (AA) — Content reflows at 320 CSS px width without horizontal scroll.
• 1.4.11 Non-text Contrast (AA) — UI components and graphics have 3:1 contrast against adjacent colors.
• 1.4.12 Text Spacing (AA) — Content adapts to user-overridden line/word/letter spacing.
• 1.4.13 Content on Hover or Focus (AA) — Tooltips and popovers are dismissable, hoverable, and persistent.

UI components and navigation must be operable.

2.1 Keyboard accessible

• 2.1.1 Keyboard (A) — All functionality is keyboard-operable.
• 2.1.2 No Keyboard Trap (A) — Focus can move away from any component using only the keyboard.
• 2.1.4 Character Key Shortcuts (A) — Single-character shortcuts can be turned off, remapped, or activate only on focus.

2.2 Enough time

• 2.2.1 Timing Adjustable (A) — Users can extend, adjust, or disable time limits.
• 2.2.2 Pause, Stop, Hide (A) — Moving, blinking, scrolling, or auto-updating content can be paused.

2.3 Seizures

• 2.3.1 Three Flashes or Below Threshold (A) — Content does not flash > 3 times per second.

2.4 Navigable

• 2.4.1 Bypass Blocks (A) — Mechanism to skip repeated content (skip-to-content link).
• 2.4.2 Page Titled (A) — Each page has a descriptive <title>.
• 2.4.3 Focus Order (A) — Focus order preserves meaning and operability.
• 2.4.4 Link Purpose (In Context) (A) — Link text alone or with context describes its purpose.
• 2.4.5 Multiple Ways (AA) — More than one way to locate a page (nav + search + sitemap).
• 2.4.6 Headings and Labels (AA) — Headings and labels describe topic or purpose.
• 2.4.7 Focus Visible (AA) — Keyboard focus indicator is visible.

2.5 Input modalities

• 2.5.1 Pointer Gestures (A) — Multipoint or path-based gestures have a single-pointer alternative.
• 2.5.2 Pointer Cancellation (A) — Actions are completed on the up-event, with abort/undo possible.
• 2.5.3 Label in Name (A) — Accessible name matches the visible label text.
• 2.5.4 Motion Actuation (A) — Motion-triggered functions have alternatives and can be disabled.

Information and operation of the UI must be understandable.

3.1 Readable

• 3.1.1 Language of Page (A) — html lang="en" (or appropriate language) is set.
• 3.1.2 Language of Parts (AA) — Parts in a different language are marked with lang.

3.2 Predictable

• 3.2.1 On Focus (A) — Focus does not trigger a context change.
• 3.2.2 On Input (A) — Input does not trigger a context change unless announced.
• 3.2.3 Consistent Navigation (AA) — Navigation appears in the same relative order across pages.
• 3.2.4 Consistent Identification (AA) — Components with the same functionality are identified consistently.

3.3 Input assistance

• 3.3.1 Error Identification (A) — Errors are identified and described to the user.
• 3.3.2 Labels or Instructions (A) — Labels or instructions are provided for user input.
• 3.3.3 Error Suggestion (AA) — Error suggestions are provided when known.
• 3.3.4 Error Prevention (Legal, Financial, Data) (AA) — For legal/financial transactions, submissions are reversible, checked, or confirmed.

Content must be robust enough to be reliably interpreted by user agents, including assistive technologies.

• 4.1.1 Parsing (A) — Obsolete in WCAG 2.2. Markup is well-formed.
• 4.1.2 Name, Role, Value (A) — UI components have a programmatic name, role, and value.
• 4.1.3 Status Messages (AA) — Status messages can be programmatically determined (ARIA live regions).

From AccessProof scans across thousands of US sites in 2024-2025, these are the recurring failure patterns:

1. Color contrast (1.4.3) — Light gray text on white, button text below 4.5:1 ratio.
2. Missing alt text (1.1.1) — Product images, icons, decorative graphics without alt or with alt="image".
3. Form inputs without labels (3.3.2) — placeholder used as label; missing <label for=> linkage.
4. Focus visible (2.4.7) — outline: none applied without a custom focus indicator.
5. Heading hierarchy (1.3.1) — <h1> missing or skipped levels (h1 → h3).
6. Link purpose (2.4.4) — "Click here", "Read more", or "Learn more" used as link text.
7. Keyboard traps in modals (2.1.2) — Custom modal dialogs that trap focus or don't restore it.
8. Non-text contrast (1.4.11) — Form input borders, button outlines below 3:1.
9. Skip links (2.4.1) — No skip-to-content link, or skip link hidden incorrectly.
10. Status messages (4.1.3) — Cart updates, error toasts not announced to screen readers.

An automated AccessProof scan flags these in 42 seconds with per-element selectors.

Each WCAG criterion has automated, semi-automated, or manual testing methods. Roughly 30-40% are reliably automatable; the rest require manual review.

• Automated (axe-core, AccessProof) — color contrast, alt text presence, ARIA validity, parsing, basic keyboard order, link/button accessible names.
• Semi-automated — focus visibility (automated detects missing outline; manual confirms quality), heading hierarchy (automated catches skips, manual confirms meaning).
• Manual only — captions accuracy, cognitive load, language-of-parts marking, motion-actuation alternatives, error-prevention workflows.

The right testing workflow is: run automated scans on every commit (AccessProof in CI), manual screen-reader + keyboard testing per major release, and accessibility-aware design review for new components.