If you've ever asked "what is WCAG?" — you're not alone. WCAG (Web Content Accessibility Guidelines) is the international standard for making websites, apps, and digital content accessible to people with disabilities. It is the technical foundation for ADA compliance, EAA compliance, and Section 508 requirements worldwide.

This comprehensive guide covers everything you need to know about WCAG — from its meaning and history to the four principles (POUR), success criteria, and how to check if your website is WCAG compliant.

What is WCAG? — Definition & Meaning

WCAG stands for the Web Content Accessibility Guidelines. It is a set of technical standards developed by the World Wide Web Consortium (W3C), the international organization that sets web standards.

WCAG provides a single shared standard for web accessibility that can be used by governments, businesses, and organizations worldwide. It is referenced by accessibility laws in over 50 countries, including:

• ADA Title II & III (USA) — Americans with Disabilities Act
• EAA (European Union) — European Accessibility Act
• Section 508 (USA) — Federal agencies and contractors
• AODA (Canada) — Accessibility for Ontarians with Disabilities Act
• UK Equality Act — United Kingdom
• DDA (Australia) — Disability Discrimination Act

The Four Principles of WCAG — POUR

WCAG is organized around four core principles, often abbreviated as POUR. For a website to be accessible, it must be:

1. Perceivable — Can Users Perceive the Content?

All users must be able to perceive the information presented on your website, regardless of their sensory abilities.

• 1.1.1 Non-text Content: All images must have descriptive alt text
• 1.4.3 Contrast (Minimum): Text must have 4.5:1 contrast ratio
• 1.4.4 Resize Text: Text must resize up to 200% without breaking

2. Operable — Can Users Navigate and Interact?

All users must be able to operate the interface, regardless of their physical abilities or the devices they use.

• 2.1.1 Keyboard: All functionality must work with a keyboard
• 2.4.7 Focus Visible: Keyboard focus must be visible
• 2.5.8 Target Size: Touch targets must be at least 24x24px

3. Understandable — Can Users Understand the Content?

All users must be able to understand the content and interface of your website.

• 3.1.1 Language of Page: Page language must be declared
• 3.3.2 Labels or Instructions: Form fields must have labels
• 3.3.1 Error Identification: Errors must be clearly identified

4. Robust — Can Assistive Technologies Read the Content?

All users must be able to access your content with a wide range of user agents, including assistive technologies.

• 4.1.2 Name, Role, Value: Custom components must have proper ARIA
• 4.1.3 Status Messages: Status updates must be announced to screen readers
• 4.1.1 Parsing: No duplicate IDs or invalid HTML

WCAG Versions — 2.0, 2.1, and 2.2

WCAG has evolved over time to address new technologies and user needs:

• WCAG 2.0 (2008): The original version, still widely used
• WCAG 2.1 (2018): Added 17 new success criteria for mobile accessibility, people with low vision, and cognitive disabilities
• WCAG 2.2 (2023): Added 9 new success criteria for better accessibility

For ADA and EAA compliance, WCAG 2.1 Level AA is the required standard.

WCAG Conformance Levels — A, AA, and AAA

WCAG has three conformance levels, each representing a higher level of accessibility:

• Level A (Minimum): The most basic accessibility requirements. Must be met for any accessibility.
• Level AA (Standard): The level required by ADA, EAA, and Section 508. This is the standard for most websites.
• Level AAA (Enhanced): The highest level of accessibility. Not required by most laws but recommended for advanced accessibility.

How to Check If Your Website Is WCAG Compliant

Step 1: Use a Free WCAG Compliance Checker

Visit AccessiTool's free ADA compliance checker and enter your website URL. The tool scans against WCAG 2.1 Level AA standards and provides a detailed report in 60 seconds.

Step 2: Review Your Compliance Report

You'll receive a compliance score (0-100%), a list of violations, warnings, and passed checks — plus specific fix recommendations for each issue.

Step 3: Fix Critical Issues First

Start with the most critical violations: missing alt text, low color contrast, keyboard accessibility issues, and missing form labels. These are the most common WCAG violations.

Step 4: Retest and Document

After making fixes, run another scan and save your PDF report for legal documentation.

Frequently Asked Questions — What is WCAG?

Internal Links — WCAG Resources