PDF to Accessible EPUB: A Practical Guide for Libraries and Accessibility Teams

Fixed-layout PDF is the single largest barrier to accessible digital content delivery. A tagged PDF can technically pass an automated accessibility checker, but it still fails readers who depend on screen readers, use e-ink devices, or need to adjust font size, spacing, and color. EPUB3 with proper accessibility metadata is a different category of document — one that is genuinely readable by every major assistive technology.

This guide is written for library staff, accessibility coordinators, and content managers who need to produce accessible EPUB from existing PDF sources.

Why EPUB3 Outperforms PDF for Accessibility

WCAG 2.2 Success Criteria and EPUB Accessibility 1.1 converge on the same requirements:

• Text must reflow to 400% zoom without loss of content (WCAG 1.4.10 Reflow): PDF fails this for most multi-column and complex layouts; EPUB passes by default.
• Reading order must be programmatically determinable (WCAG 1.3.2): PDF reading order depends on tag structure and is frequently wrong; EPUB reading order is explicit in the document structure.
• Navigation landmarks must exist (WCAG 2.4.1, 2.4.6): EPUB3 requires a table of contents and supports landmark navigation (chapters, sections); PDF requires manually tagged structure that is often missing.
• Language must be specified (WCAG 3.1.1, 3.1.2): EPUB3 requires a language declaration; PDF language tags are often missing.

For readers using JAWS, NVDA, VoiceOver, or Dolphin, EPUB3 produced from a well-structured source PDF provides a significantly better experience than the equivalent tagged PDF.

When to Convert PDF to EPUB

This approach is appropriate when:

• A patron requests an accessible version of a PDF document already in your collection
• You receive a PDF from a publisher or author that needs to be made accessible before distribution
• Staff need to convert supplemental reading materials for courses or training
• A document needs to be readable on e-ink devices (Kindle, Kobo) or mobile apps that don't render PDF accessibly

How to Convert PDF to Accessible EPUB

1. Go to toolkit.bot/pdf2epub
2. Upload the PDF
3. Download the EPUB3 file (typically ready in 30 seconds)
4. Open in a screen reader or EPUB validator to verify output quality

The tool produces EPUB3 files with semantic HTML5 structure (headings mapped to H1–H6), language declaration, alt text for images extracted from PDF alt text where present, table structure preserved where tables are detected in the source PDF, and EPUB Accessibility 1.1 metadata.

Common Issues and How to Handle Them

• Headings not detected: If the source PDF doesn't use font size or style consistently to indicate headings, the EPUB may produce a flat structure. For high-priority documents, manually add heading structure in an EPUB editor (Sigil is free) after conversion.
• Reading order errors in two-column PDFs: Multi-column academic papers sometimes produce incorrect reading order. Check with a screen reader; if the order is wrong, the document may need manual cleanup.
• Scanned PDFs: If the PDF was created from a scan with no text layer, the converter uses OCR fallback. OCR accuracy depends on scan quality. For accessibility-critical documents from scanned sources, a human review of the OCR output is recommended before distribution.
• Missing alt text on figures: If the source PDF lacks alt text on images, the EPUB will also lack it. For accessibility compliance, add alt text in an EPUB editor after conversion.

Resources for Library Accessibility Teams

• EPUB Accessibility 1.1 specification — W3C
• ACE by DAISY — free EPUB accessibility checker
• EPUBCheck — free EPUB validator