WCAG A, AA, and AAA: Which Level Do You Need?

WCAG (Web Content Accessibility Guidelines) is organized into three levels: A, AA, and AAA. But what do these levels actually mean, and which should you aim for?

The levels represent different degrees of accessibility – from basic requirements that make websites usable at all, to optimal accessibility that maximizes inclusion.

In this guide, we explain each level, give examples of criteria, and help you decide which ambition level fits your organization.

Overview of the levels

Level A (Basic):

Level AA (Standard):

Level AAA (Optimal):

Important: Levels are cumulative. To reach AA, you must meet all A criteria PLUS all AA criteria.

Think of it like stairs: You can't jump to step 2 without standing on step 1 first.

Level A – Basic accessibility

Level A criteria are foundational. If you don't meet these, the site is likely unusable for some groups.

Example A criteria:

1.1.1 Non-text Content:

Images must have text alternatives (alt text). Without this, blind users can't know what the image shows.

2.1.1 Keyboard:

All functionality must be accessible via keyboard. If a menu only works with mouse, keyboard users can't navigate.

2.1.2 No Keyboard Trap:

Users must not get trapped in keyboard traps. If focus lands in a modal that can't be closed with keyboard, they're stuck.

3.3.1 Error Identification:

Input errors must be identified and described. A form that only marks fields red without text doesn't help color-blind users.

4.1.1 Parsing:

HTML code must be correct. Duplicate IDs or incomplete tags break assistive technology.

Level AA – The legal requirement

AA is the level most laws reference. It's a practical balance – accessible enough to work for most people, but not so strict it becomes impractical.

Example AA criteria:

1.4.3 Contrast (Minimum):

Text must have at least 4.5:1 contrast against background (3:1 for large text). This is one of the most common issues on the web.

1.4.4 Resize Text:

Text must be resizable to 200% without loss of content or functionality. Layout may break but information must not disappear.

2.4.7 Focus Visible:

Keyboard focus must be visible. Users must be able to see which link/button is selected.

3.3.3 Error Suggestion:

If input error is detected, suggestion for correction should be given (if possible). 'Enter email as name@domain.com' – not just 'Invalid email'.

1.4.11 Non-text Contrast (WCAG 2.1):

Graphical components (icons, form fields, buttons) must have 3:1 contrast against surroundings.

Level AAA – Optimal accessibility

AAA represents optimal accessibility. WCAG acknowledges it's not always possible to achieve AAA for all content.

Example AAA criteria:

1.4.6 Contrast (Enhanced):

Contrast 7:1 for normal text, 4.5:1 for large text. Significantly harder to achieve with colorful brands.

1.4.9 Images of Text (No Exception):

No text in images at all, not even with exceptions for logos (which A allows).

2.2.3 No Timing:

No time limits at all, except real-time events and situations where time is essential.

3.1.5 Reading Level:

Content should be understandable for people with lower secondary education, or supplementary versions should be available.

Why AAA is hard:

Some AAA criteria conflict. 3.1.5 (reading level) can clash with technical content. 1.4.6 (7:1 contrast) can clash with brand colors.

Which level should you choose?

Minimum (legal requirement): AA

If you don't meet AA, you risk fines and legal problems after June 2025. This is non-negotiable for covered organizations.

Recommendation: AA + selected AAA

Aim for full AA compliance and add AAA criteria where practical and meaningful for your audience.

Which AAA criteria to prioritize:

Special cases:

If your audience includes seniors or people with specific disabilities (e.g., a disability services agency), consider higher AAA adoption.

Practical advice:

Build to AA first. Document which AAA criteria you meet or aim for. Be transparent in your accessibility statement.