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

What Is a WCAG Audit?

A WCAG audit is a systematic evaluation of a website or web application to determine how well it conforms to the Web Content Accessibility Guidelines (WCAG). Published by the World Wide Web Consortium (W3C), WCAG defines a set of technical standards designed to make digital content accessible to people with disabilities — including those with visual, auditory, motor, and cognitive impairments.

Whether you're a developer, designer, or business owner, conducting a WCAG audit is one of the most important steps you can take toward building an inclusive digital experience — and staying on the right side of accessibility 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 accessing information, services, and opportunities that others take for granted. Beyond the ethical obligation, there are strong legal and business reasons to conduct regular WCAG audits:

• Legal compliance: In many countries, failing to meet accessibility standards can result in lawsuits, fines, and reputational damage.
• Wider audience reach: An accessible site serves more users, including older adults and people with temporary disabilities.
• Better SEO: Many WCAG best practices (like alt text, proper heading structure, and descriptive links) also improve your search engine rankings.
• Improved UX: Accessibility improvements often enhance usability for all users, not just those with disabilities.

Understanding WCAG Levels: A, AA, and AAA

WCAG is organized into three levels of conformance:

• Level A: The minimum level of conformance. Covers the most basic accessibility features that are absolutely essential.
• Level AA: The standard required by most laws and regulations, including the ADA and EAA. This is the target for most organizations.
• Level AAA: The highest and most stringent level. Not typically required by law, but recommended for organizations serving users with specific accessibility needs.

Most WCAG audits focus on achieving WCAG 2.1 AA or WCAG 2.2 AA conformance, which together address a comprehensive range of disability-related barriers.

The Four Principles of WCAG (POUR)

Every WCAG success criterion falls under one of four core principles, collectively known as POUR:

• Perceivable: Information and UI components must be presentable to users in ways they can perceive (e.g., alt text for images, captions for video).
• Operable: UI components and navigation must be operable (e.g., keyboard accessibility, no seizure-inducing content).
• Understandable: Information and UI operation must be understandable (e.g., clear language, predictable navigation).
• Robust: Content must be robust enough to be interpreted by 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 or sections of your website will be audited. For large sites, prioritize high-traffic pages, checkout flows, contact forms, and any pages where users perform critical actions.

Step 2: Use Automated Scanning Tools

Automated tools can quickly identify a significant portion of WCAG violations. Popular options include:

• Alt Audit: Specializes in detecting missing or inadequate alt text across your entire site, making it ideal for image-heavy websites.
• axe DevTools: A browser extension that catches a wide range of WCAG issues directly in your development workflow.
• WAVE (Web Accessibility Evaluation Tool): A free visual tool that overlays accessibility errors and warnings on your live site.
• Lighthouse: Built into Chrome DevTools, it provides an accessibility score along with actionable recommendations.

Keep in mind that automated tools typically catch around 30–40% of all WCAG issues. Manual testing is essential to uncover the rest.

Step 3: Perform Manual Testing

Manual testing involves reviewing your site with human judgment and real assistive technologies. Key areas to check include:

• Keyboard navigation: Can every interactive element be reached and operated using only a keyboard?
• Screen reader testing: Use tools like NVDA (Windows), JAWS, or VoiceOver (Mac/iOS) to verify that content is read correctly.
• Color contrast: Ensure text meets WCAG's minimum contrast ratios (4.5:1 for normal text, 3:1 for large text).
• Form accessibility: All form 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 that documents each issue found, the WCAG success criterion it violates, the severity level (critical, major, minor), and recommended remediation steps. A well-structured report is invaluable for your development team when prioritizing fixes.

Step 5: Remediate and Retest

Work through your findings systematically, starting with the most critical issues. Once fixes are implemented, retest to confirm that each issue has been properly resolved and that no new issues were introduced in the process.

Common WCAG Failures to Watch For

Across thousands of web accessibility audits, certain issues appear again and again. The most common WCAG failures include:

• Missing or empty alt text on images
• Insufficient color contrast between text and background
• Form inputs without associated labels
• Links with non-descriptive text (e.g., "click here" or "read more")
• Videos without captions or transcripts
• Pages that can't be navigated by keyboard alone
• Missing skip navigation links on pages with repeated content
• Inaccessible PDF documents

How Often Should You Conduct a WCAG Audit?

Accessibility is not a one-time fix — it's an ongoing commitment. Best practice is to conduct a full WCAG audit at least once a year, as well as whenever significant changes are made to your site (new templates, redesigns, major feature launches). Integrating automated scanning into your CI/CD pipeline can help 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 not only protect your organization from legal risk but also create a better experience for every visitor.

Ready to get started? Alt Audit makes it easy to identify missing and inadequate alt text across your entire website — one of the most common and impactful WCAG failures. Run your first scan today and take a meaningful step toward full accessibility compliance.