What Accessibility Checker Should I Use for PDFs?

If you have a stack of PDFs and need to know whether they meet accessibility standards, you are not short on options. The real question is which tool fits your situation — a quick spot check, a deep compliance audit, or something that can fix problems as it finds them.

Here is the short answer: it depends on what you need.

• For a quick check, Adobe Acrobat's built-in checker works.
• For thorough validation, PAC (PDF Accessibility Checker) is the best free tool available.
• For comprehensive standards compliance, veraPDF checks 108 PDF/UA rules and is the most rigorous option.
• For checking and fixing in one step, you want a remediation platform rather than a standalone checker.

Let's break down the options.

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1. Adobe Acrobat Pro

Best for: Quick checks when you already have Acrobat installed.

Adobe Acrobat Pro includes a built-in accessibility checker under Tools > Accessibility. It runs through a set of checks covering document structure, alt text presence, reading order, and color contrast.

Strengths:

• Already installed on most university and enterprise machines
• Integrated with Acrobat's editing tools so you can fix some issues on the spot
• Generates a clear pass/fail report with explanations

Limitations:

• Catches the basics but misses many structural issues that matter for screen reader users
• Does not validate against the full Matterhorn Protocol or PDF/UA specification
• Requires a paid Creative Cloud subscription
• Can give false confidence — a document can pass Acrobat's checks and still have significant accessibility problems

If Acrobat is all you have, it is a reasonable starting point. Just know that passing its checker does not mean your PDF is fully accessible.

2. PAC 2024 (PDF Accessibility Checker)

Best for: Anyone who wants a thorough, free accessibility check.

PAC is built by the PDF/UA Foundation — the same organization behind the PDF/UA standard. It checks documents against the Matterhorn Protocol, which defines failure conditions for PDF accessibility. PAC 2024 is the latest version and remains the gold standard among free checkers.

Strengths:

• Free to use
• Checks against the Matterhorn Protocol, far more thorough than Acrobat
• Includes a built-in screen reader preview so you can experience the document the way assistive technology users do
• Clear, detailed reporting with specific failure references

Limitations:

• Windows only (though it runs well under virtualization on Mac)
• Checks for problems but cannot fix them
• Some checks still require manual judgment — PAC flags what it can, but not everything is automatable

PAC is the tool we recommend most often for faculty, content creators, and accessibility coordinators. If you are only going to use one checker, make it this one.

3. veraPDF

Best for: IT teams and compliance officers who need the most comprehensive validation.

veraPDF is an open-source validator originally built for PDF/A archival compliance and extended to cover PDF/UA. It checks 108 PDF/UA rules and is the most technically rigorous option available.

Strengths:

• Open source and free
• 108 PDF/UA validation rules — the most comprehensive rule set of any checker
• Batch processing via command line, ideal for checking hundreds or thousands of files
• Machine-readable output (XML/JSON) for integration into automated workflows

Limitations:

• Command-line interface is less approachable for non-technical users
• No built-in screen reader preview
• Steep learning curve for interpreting results
• Checks only — no remediation capability

veraPDF is the right choice when you need to audit a large document library systematically or when compliance documentation requires the most defensible validation evidence.

4. PAVE

Best for: Quick web-based checks without installing software.

PAVE is a free, web-based tool from a Swiss research project. Upload a PDF and it identifies accessibility issues, with some ability to apply automatic fixes to simple problems like missing tags.

Strengths:

• No installation required — runs in your browser
• Some automatic fixing capability for basic structural issues
• Simple interface suitable for non-technical users

Limitations:

• File size limits restrict use with larger documents
• Auto-fix capabilities are limited to straightforward issues
• Less thorough than PAC or veraPDF
• Uploading sensitive documents to a third-party service may raise privacy concerns

5. Tingtun

Best for: A fast, WCAG-focused check without installing anything.

Tingtun offers a free online PDF checker that evaluates documents against WCAG 2.1 criteria. It is straightforward and produces easy-to-read reports.

Strengths:

• Free and web-based
• WCAG-focused reporting that maps findings to specific success criteria
• Quick turnaround on results

Limitations:

• Less comprehensive than PAC or veraPDF
• Does not check against Matterhorn Protocol or full PDF/UA specification
• Same third-party upload concerns as PAVE

6. CommonLook

Best for: Large enterprises with significant budgets and high-volume needs.

CommonLook is a commercial, enterprise-grade suite that includes both checking and remediation tools. It is widely used by large organizations and accessibility service providers.

Strengths:

• Comprehensive checking and remediation in one toolset
• Strong support and training resources
• Handles complex documents well

Limitations:

• Expensive — pricing is typically in the thousands per license
• Overkill for smaller teams or occasional use
• Significant training investment required

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Which Tool Should You Use?

| If you are... | Start with | |---|---| | A faculty member checking your own course materials | PAC 2024 | | An IT team auditing a document library | veraPDF (batch mode) | | Someone who needs a quick check right now | Adobe Acrobat Pro or PAVE | | An enterprise with budget and volume | CommonLook or a combined approach |

For most higher education teams, PAC 2024 is the best starting point. It is free, thorough, and built by the people who wrote the standard.

If you need to audit at scale, pair PAC with veraPDF's batch processing to cover both the Matterhorn Protocol and the full PDF/UA rule set.

The Limitation Every Checker Shares

No automated checker — not even veraPDF with its 108 rules — can tell you whether your alt text actually makes sense. It can confirm that alt text exists, but it cannot judge whether "chart" is a sufficient description of a complex data visualization, or whether a decorative image has been correctly marked as an artifact.

Automated tools catch structural and technical failures. Contextual quality still requires human judgment — or AI that understands the content, not just the tags.

This is the gap between checking and truly fixing. For a deeper look at what automated scanning can and cannot do, see our post on why most PDF accessibility tools only find problems. And if you are new to the checking process itself, our step-by-step guide to checking PDF accessibility walks through the full workflow.

Checking Is Only Half the Job

Finding problems is important. Fixing them is what actually makes documents accessible. Most of the tools above are excellent at identifying issues but leave the remediation work entirely to you — and manual PDF remediation is slow, technical, and tedious.

Aelira combines Matterhorn and veraPDF validation with automated remediation — check and fix in one pipeline. See how it works.