- Multi-format Support: Reads EPUB 2, EPUB 3, fixed-layout EPUBs, PDFs, DAISY books, audiobooks, and Divina publications.
- Accessibility First: Optimized for screen readers like NVDA, JAWS, and VoiceOver, supporting visually impaired and dyslexic readers.
- LCP DRM Compatibility: Opens LCP-protected EPUBs, PDFs, audiobooks, and other supported formats.
- Advanced Reading Controls: Customize fonts, spacing, colors, brightness, columns, and reading modes including night and sepia.
- OPDS Catalog Browsing: Browse, authenticate, and borrow from OPDS 1 and 2 digital library catalogs.
- Read Aloud & Media Overlays: Supports synchronized text-to-speech and EPUB media overlays.
- Annotations & Bookmarks: Create shareable annotations, bookmarks, and manage reading positions.
Edrlab Thorium Reader
Free, open-source, highly accessible EPUB and digital publication reader
Updated August 3, 2026
Edrlab Thorium Reader Overview
Thorium Reader is a free, open-source desktop reader from EDRLab for Windows, macOS, and Linux. EDRLab describes EPUB, PDF, DAISY, audiobooks, and accessible reading as core use cases, with no ads and no private-data business model.
Donations fund development; they are not a subscription price for the reader itself.
Key Features
Pricing
| Plan | Price | Featured |
|---|---|---|
| Thorium Reader | $0 (free and open source) | EPUB, PDF, DAISY, audiobooks, and accessibility features |
Pricing source: https://www.edrlab.org/software/thorium-reader/
Pros
Competitor |
Pros |
|---|---|
| Adobe Digital Editions | Compared with Adobe Digital Editions, this page’s product centers on a free, open-source accessible ebook reader. Its no ads, no private-data business model, and accessibility work across desktop platforms is useful for readers, libraries, and students using EPUB, PDF, DAISY, and audiobooks, especially when the goal is reading protected and reflowable publications rather than managing a document library; Adobe Digital Editions remains the alternative when that buyer needs a different emphasis. |
| Calibre | Compared with Calibre, this page’s product centers on a free, open-source accessible ebook reader. Its no ads, no private-data business model, and accessibility work across desktop platforms is useful for readers, libraries, and students using EPUB, PDF, DAISY, and audiobooks, especially when the goal is reading protected and reflowable publications rather than managing a document library; Calibre remains the alternative when that buyer needs a different emphasis. |
| Bookworm | Compared with Bookworm, this page’s product centers on a free, open-source accessible ebook reader. Its no ads, no private-data business model, and accessibility work across desktop platforms is useful for readers, libraries, and students using EPUB, PDF, DAISY, and audiobooks, especially when the goal is reading protected and reflowable publications rather than managing a document library; Bookworm remains the alternative when that buyer needs a different emphasis. |
Cons
Competitor |
Cons |
|---|---|
| Adobe Digital Editions | Compared with Adobe Digital Editions, this product is narrower around a free, open-source accessible ebook reader. Teams that need a commercial publishing ecosystem with broader vendor support may prefer Adobe Digital Editions; the trade-off is less emphasis on the workflow described here. |
| Calibre | Compared with Calibre, this product is narrower around a free, open-source accessible ebook reader. Teams that need a commercial publishing ecosystem with broader vendor support may prefer Calibre; the trade-off is less emphasis on the workflow described here. |
| Bookworm | Compared with Bookworm, this product is narrower around a free, open-source accessible ebook reader. Teams that need a commercial publishing ecosystem with broader vendor support may prefer Bookworm; the trade-off is less emphasis on the workflow described here. |
Reviews
- Reddit r/software: One commenter highlighted that Edrlab Thorium Reader properly supports vertical Japanese EPUBs, calling it the only Western-developed reader that handles them correctly, and also praised its strong accessibility with DAISY and PDF support for visually impaired readers. Another user felt disappointed after using it for an LCPL file, while someone else criticized its Electron base for consuming too many system resources compared to lighter EPUB readers.
- erdalozkaya.com Review: Edrlab Thorium Reader earns praise for its accessibility toolkit, including text-to-speech, dyslexic font options, and compatibility with NVDA and JAWS, along with solid EPUB 3 and DAISY support. The reviewer notes occasional performance hiccups with very large or complex EPUB files, limited visual customization, and the lack of a mobile version as clear drawbacks.
- klaava.com Review: Edrlab Thorium Reader impressed the reviewer with simple but thoughtful touches such as two-page viewing on large screens and a scrolling mode that feels as natural as reading a web page. The R2 Reader mobile prototype adds text-to-speech for reading aloud, though it currently lacks adjustable speed and broad language selection, and the app reassures privacy-conscious readers by keeping user data from leaking.
