PDF Accessibility Checker - Check PDFs for Screen Reader Compatibility

Published March 25, 2026

An accessible PDF can be read and navigated by anyone — including people who use screen readers, keyboard navigation, or other assistive technologies. If you create PDFs for public or professional use, checking PDF accessibility is essential for compliance with ADA, WCAG, and Section 508 requirements. This guide covers free tools to check and fix PDF accessibility issues.

What Makes a PDF Accessible?

An accessible PDF meets several technical requirements that allow assistive technologies to interpret and convey the document content:

  • Tagged PDF: Every element (headings, paragraphs, images, tables) has a tag that defines its role and structure
  • Reading order: Content is ordered logically so screen readers read it in the correct sequence
  • Alt text for images: Images have alternative text descriptions for screen readers
  • Accessible fonts: Text uses embedded fonts that can be extracted and read
  • Color contrast: Text has sufficient contrast against background colors
  • Form fields labeled: Interactive form fields have descriptive labels
  • Language specified: The document language is set so screen readers use the correct pronunciation
  • No security restrictions: Security settings don't block assistive technology access

Free PDF Accessibility Checkers

Adobe Acrobat Accessibility Checker (Free in Reader)

Adobe Acrobat Pro has the most comprehensive built-in accessibility checker, but even the free Acrobat Reader can run basic accessibility checks:

  • Open your PDF in Adobe Acrobat
  • Go to Tools > Accessibility > Full Check (Acrobat Pro) or Accessibility Report
  • Acrobat checks for tags, reading order, alt text, color contrast, and more
  • Results show pass/fail for each accessibility criterion with explanations

Acrobat Pro (paid) offers the "Make Accessible" wizard to automatically fix many issues. The free Reader version can view accessibility reports but not run the full check.

PAC 2024 (PDF Accessibility Checker) — Free

PAC (PDF Accessibility Checker) by PDF/UA Foundation is a powerful free desktop tool for Windows:

  • Download free from pdfua.foundation
  • Drag and drop any PDF to run a comprehensive accessibility audit
  • Checks against PDF/UA (ISO 14289) and WCAG standards
  • Provides a detailed report with pass/fail results and issue descriptions
  • Shows the document structure view (tags tree) for manual inspection

PAC 2024 is considered the gold standard for free PDF accessibility checking by accessibility professionals.

axesCheck — Free Online PDF Checker

axesCheck (axescheck.com) is a free online tool that checks PDFs for WCAG and PDF/UA compliance:

  • Upload your PDF (up to 10MB)
  • Get an automated accessibility report in minutes
  • Results show which criteria pass and which fail
  • No software installation required

Common PDF Accessibility Issues and How to Fix Them

Issue: Untagged PDF

Scanned PDFs or PDFs created from images are often completely untagged — meaning screen readers can't interpret the content structure at all.

Fix: In Adobe Acrobat Pro, use Tools > Accessibility > Add Tags to Document. For scanned documents, run OCR first, then tag the result.

Issue: Missing Alt Text on Images

Images without alt text are invisible to screen readers — users with visual impairments can't know what the image shows.

Fix: In Acrobat Pro, right-click each image tag > Properties > add an Alternative Text description. For decorative images, mark them as "Artifact" so screen readers skip them.

Issue: Wrong Reading Order

Multi-column layouts or complex page designs often have content tagged in visual order rather than logical reading order.

Fix: Use the Reading Order tool in Acrobat Pro to manually set the correct sequence. Check with the Order panel to see how screen readers will navigate the document.

Issue: Low Color Contrast

Text that doesn't have sufficient contrast against the background is hard to read for users with low vision or color blindness.

Fix: WCAG requires a contrast ratio of 4.5:1 for normal text. Use WebAIM's Contrast Checker or Adobe Color to verify contrast ratios. Fix in the source document and regenerate the PDF.

PDF Accessibility Standards

  • WCAG 2.1 AA: Web Content Accessibility Guidelines — the international standard for digital accessibility
  • PDF/UA (ISO 14289): The PDF Universal Accessibility standard specifically for PDFs
  • Section 508: US federal requirement for accessible electronic documents
  • ADA (Americans with Disabilities Act): US law requiring accessible public digital content
  • EN 301 549: European accessibility standard for ICT products and services

Frequently Asked Questions

Is there a free PDF accessibility checker?
Yes — PAC 2024 (Windows desktop) and axesCheck (online) are both free and check against professional PDF/UA and WCAG standards.

What is a tagged PDF?
A tagged PDF has a hidden structure layer (the "tag tree") that describes the role of every element — heading, paragraph, image, table, etc. Screen readers use tags to navigate and understand the document.

Do I need Adobe Acrobat to make a PDF accessible?
Adobe Acrobat Pro is the most powerful tool for remediating PDFs, but you can also create accessible PDFs at the source (in Microsoft Word or LibreOffice with accessibility features enabled) before exporting to PDF.

Can I check if a PDF is accessible without software?
Yes — use axesCheck online (axescheck.com) or upload your PDF to PeacefulPDF for a quick accessibility assessment.