WCAG Audit: A Complete Guide to Testing and Fixing Web Accessibility

A WCAG audit is a systematic evaluation of your website to determine how well it conforms to the Web Content Accessibility Guidelines (WCAG) — the globally recognized standards published by the W3C for making digital content accessible to people with disabilities.

Whether you're a developer, designer, or business owner, conducting a WCAG audit is one of the most important steps toward building an inclusive digital experience and staying compliant with laws like the ADA, Section 508, and the European Accessibility Act (EAA).

Why WCAG Audits Matter

Over 1 billion people worldwide live with some form of disability. When websites aren't accessible, these users are excluded from information and services. Beyond ethics, there are strong legal and business reasons to audit regularly:

• Legal compliance: Failing to meet accessibility standards can result in lawsuits and fines
• Wider reach: Accessible sites serve more users, including older adults and those with temporary disabilities
• Better SEO: Alt text, proper headings, and descriptive links also improve search rankings
• Improved UX: Accessibility improvements benefit all users

Understanding WCAG Levels: A, AA, and AAA

WCAG is organized into three conformance levels:

• Level A: Minimum baseline — absolute essentials
• Level AA: Required by most laws (ADA, EAA) — the standard target for most organizations
• Level AAA: Highest level — not typically required by law but recommended for specialized use

Most audits target WCAG 2.1 AA or WCAG 2.2 AA.

The Four Principles of WCAG (POUR)

Every WCAG success criterion falls under one of four core principles:

1. Perceivable — Content must be presented in ways users can perceive (e.g., alt text for images, captions for video)
2. Operable — UI must be operable (e.g., keyboard accessibility, no seizure-inducing content)
3. Understandable — Content must be understandable (e.g., clear language, predictable navigation)
4. Robust — Content must work with assistive technologies (e.g., valid HTML, ARIA attributes)

How to Conduct a WCAG Audit: Step-by-Step

Step 1: Define the Scope

Decide which pages to audit. Prioritize high-traffic pages, checkout flows, contact forms, and critical user journeys.

Step 2: Use Automated Scanning Tools

Automated tools can catch around 30–40% of WCAG issues:

• Alt Audit — Detects missing or inadequate alt text across your entire site
• axe DevTools — Browser extension catching a wide range of WCAG issues in your dev workflow
• WAVE — Free visual tool that overlays accessibility errors on your live site
• Lighthouse — Built into Chrome DevTools, provides an accessibility score with recommendations

Step 3: Perform Manual Testing

Manual testing uncovers what automation misses:

• Keyboard navigation — Can every element be reached and used with only a keyboard?
• Screen reader testing — Use NVDA, JAWS, or VoiceOver to verify content is read correctly
• Color contrast — Ensure text meets minimum ratios (4.5:1 for normal text, 3:1 for large text)
• Form accessibility — All inputs should have proper labels, error messages, and instructions
• Focus indicators — Visible focus states must be present for all interactive elements

Step 4: Document Your Findings

Create a detailed audit report covering:

• Each issue found
• The WCAG criterion it violates
• The severity level (critical, major, minor)
• Recommended remediation steps

Step 5: Remediate and Retest

Work through findings systematically, starting with the most critical issues. Retest after each fix to confirm resolution and check for regressions.

Common WCAG Failures to Watch For

These are the most frequently encountered accessibility failures:

• Missing or empty alt text on images
• Insufficient color contrast
• Form inputs without associated labels
• Non-descriptive link text ("click here", "read more")
• Videos without captions or transcripts
• Pages that can't be navigated by keyboard
• Missing skip navigation links
• Inaccessible PDF documents

How Often Should You Audit?

Accessibility is an ongoing commitment, not a one-time fix. Best practice:

• Conduct a full audit at least once a year
• Audit after significant changes (redesigns, new templates, major feature launches)
• Integrate automated scanning into your CI/CD pipeline to catch regressions early

Start Your WCAG Audit Today

A WCAG audit is the foundation of any serious accessibility program. By identifying and fixing barriers on your website, you protect your organization from legal risk and create a better experience for every visitor.

One of the most common and impactful WCAG failures is missing or inadequate alt text. Tools like Alt Audit make it easy to scan your entire site, identify images with missing alt text, and fix them at scale with AI.

Originally published at altaudit.com