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How to check the accessibility of a PDF

Updated October 14, 2026 · 6 min read

A PDF can be just as inaccessible as a web page: a scanned image without text, no headings, a reading order that jumps between columns, tables a screen reader cannot follow. To check a PDF you need a PDF accessibility checker plus a few manual checks. The two most widely used checkers are the Accessibility Checker in Adobe Acrobat Pro and the free PAC by axes4. Both test against PDF/UA (ISO 14289) and parts of WCAG.

One thing up front: Pandus checks web pages, not the content of PDF files. Our WCAG checker tests the HTML page that links to your PDF, not the PDF itself. This page explains how to check the PDFs. It is general information, not legal advice.

Which rules apply to PDFs

PDF/UA (ISO 14289)

PDF/UA — PDF for Universal Accessibility — is the ISO standard for accessible PDF files. It defines how a file must be built so that assistive technology can use it: a complete tag structure, a defined reading order, real text with fonts that map to Unicode, alternative text for figures, a document title and language.

  • ISO 14289-1 (PDF/UA-1) builds on PDF 1.7 (ISO 32000-1); the current edition is from 2014.
  • ISO 14289-2 (PDF/UA-2), published in 2024, builds on PDF 2.0 (ISO 32000-2).

The PDF Association's Matterhorn Protocol turns the PDF/UA-1 requirements into a list of testable failure conditions; checkers such as PAC are based on it.

WCAG and EN 301 549 chapter 10

WCAG is written for web content, but its success criteria are applied to documents too. In the European Union, the harmonised standard EN 301 549 has a separate chapter 10 for non-web documents, which takes over most WCAG criteria at levels A and AA for documents such as PDF, Word and spreadsheet files. Under the European Accessibility Act, a PDF that customers need — terms, an invoice, a product manual, a booking confirmation — is part of the service.

In the US, Section 508 applies the WCAG 2.0 AA criteria to electronic documents of federal agencies, which is why people also search for a "508 compliance checker for PDF".

Automated PDF accessibility checkers

Adobe Acrobat Pro: Accessibility Checker

Acrobat Pro includes an Accessibility Checker and accessibility tools for fixing tags and reading order. Open the PDF, open the accessibility tools, run the full check and choose the options. Each rule in the result has one of four statuses: Passed, Skipped by user, Needs manual check or Failed. The panel links to hints for fixing each issue, and you can save a report.

Keep in mind:

  • the checker cannot tell essential content from decoration, so review each finding;
  • the Needs manual check items — such as logical reading order and colour contrast — are your job;
  • the checker is a feature of Acrobat Pro, which is a paid product.

PAC (PDF Accessibility Checker)

PAC, published by axes4, is a free desktop checker that has existed since 2010. The current release is PAC 2026. It runs on Windows 10 and 11 (with .NET Framework 4.8 or newer) and installs without administrator rights. PAC tests against PDF/UA and WCAG, implements the Matterhorn Protocol and adds a visual check and, since the 2026 release, AI-assisted checks. Its development is funded by the German Federal Ministry of Labour and Social Affairs. Download: pac.pdf-accessibility.org.

Other options

Several document tools and libraries check PDF/UA as well, for example the open-source veraPDF validator for PDF/UA-1. Office applications such as Word have their own accessibility checkers; fixing the source document before exporting is usually easier than repairing the PDF.

Manual checks no checker does

Automated PDF checkers confirm that tags exist; they cannot tell whether the tags make sense. Check by hand:

  1. Real text. Select text with the cursor. If you cannot, the page is a scanned image and needs text recognition (OCR) and tagging.
  2. Reading order. Read the tag tree or the reading order view: does it follow the visual order, column by column, without footers in the middle of a sentence?
  3. Headings. Headings are tagged H1, H2 and so on, in a logical hierarchy, and the document has a title.
  4. Alternative text. Figures that carry information have a meaningful description; decorative images are marked as artifacts.
  5. Tables. Header cells are tagged as headers; complex tables are split or simplified.
  6. Links. Link text says where it goes, not only "click here".
  7. Forms. Fields have names and tooltips and can be filled with the keyboard in a logical order.
  8. Language. The document language is set, and passages in other languages are marked.
  9. Contrast and colour. Text contrast of at least 4.5:1 (3:1 for large text); colour is not the only signal. Use our contrast checker for the colour pairs.
  10. Screen reader test. Open the PDF with NVDA or VoiceOver and read a few pages.

Make accessible PDFs at the source

  • Write the document in Word, InDesign or another tool with real headings, lists and table headers.
  • Add alternative text in the source, not later in Acrobat.
  • Export with tags: use the export option that creates a tagged PDF, then check it with PAC or Acrobat.
  • For long or legally important documents, consider whether an HTML page would serve customers better. A web page is easier to make accessible, adapts to a phone and is covered by your website monitoring.

Where Pandus helps — and where not

Pandus checks the web pages of your site every week: the page that offers the PDF, its link text, the language of the page and everything else on it. It does not open, parse or test the content of PDF files. For the PDFs, use the checkers above and the manual list; for an overall picture, see how to test WCAG and, if you need a statement of conformance, an accessibility audit.

Frequently asked questions

How do I check if a PDF is accessible?

Run an automated checker such as the Accessibility Checker in Adobe Acrobat Pro or the free PAC, fix what it reports, and then check by hand: reading order, meaningful alternative text, headings, table headers, language and contrast.

What is PDF/UA?

PDF/UA (Universal Accessibility) is the ISO 14289 standard for accessible PDF files. Part 1, PDF/UA-1, builds on PDF 1.7; part 2, PDF/UA-2 from 2024, builds on PDF 2.0. It defines how tags, structure, fonts and metadata must be set up.

Is there a free PDF accessibility checker?

Yes. PAC, published by axes4, is a free desktop checker for Windows that tests PDFs against PDF/UA and WCAG. The Accessibility Checker in Adobe Acrobat is part of Acrobat Pro, which is paid.

Does WCAG apply to PDF files?

Yes, in practice. In the EU, EN 301 549 chapter 10 applies WCAG-based requirements to non-web documents such as PDFs. A PDF published on a website is also content of that website for its visitors.

Does Pandus check PDF files?

No. Pandus checks web pages. It does not open or test the content of PDF files linked from those pages; use a PDF checker for them.

Sources

  • axes4, PAC — PDF Accessibility Checker: https://pac.pdf-accessibility.org/en and https://pac.pdf-accessibility.org/en/download
  • Adobe, Create and verify PDF accessibility (Acrobat Pro): https://helpx.adobe.com/acrobat/current/create-verify-pdf-accessibility.html
  • Adobe, PDF accessibility overview: https://www.adobe.com/accessibility/pdf/pdf-accessibility-overview.html
  • ISO 14289-2:2024 (PDF/UA-2): https://www.iso.org/standard/82278.html
  • PDF Association, Matterhorn Protocol: https://pdfa.org/resource/the-matterhorn-protocol/