Thorium Reader is the EPUB reader of choice for Windows 10 and 11, MacOS and Linux.
This EDRLab application is in constant development and aims at becoming a reference for accessing EPUB 3 publications in reflow or fixed-layout format, audiobooks and visual narratives, PDF documents and DAISY 2.02 and 3 accessible ebooks, LCP protected or not.
It is localised in a large set of languages, each version offering new locales.
Massive efforts are also made to make Thorium Reader highly accessible for visually impaired and dyslexic people.
Publisher’s description
What is Thorium?
Thorium by EDRLab is open-source Windows software in the e-book readers category. It ranks 37th by popularity among e-book readers in this catalogue. It is written in TypeScript.
Installation and requirements
The publisher provides EXE (NSIS) installers for 64-bit and ARM64 Windows. It can be installed for the current user only, without administrator rights. A silent install is possible with the installer’s documented switches.
Updates and version history
The current version is 3.5.1, released on September 2, 2026. The version history goes back to August 9, 2022: 13 releases, all linked to the official files. That is about 3.2 releases a year.
Popularity and file types
The source code on GitHub (edrlab/thorium-reader) has 2,912 stars. On Windows it registers 9 file types, including .epub, .epub3, .audiobook, .daisy and .lcpa. Similar programs include calibre, SumatraPDF and Sigil.
Project description on GitHub: “A cross platform desktop reading app, based on the Readium Desktop toolkit”
Pros / Cons
Pros
- Open source: the code can be inspected and built by anyone
- Native ARM64 build for Windows on Arm
- Documented silent install
- Installs without administrator rights
- Updated in the last two months
In short: Thorium is an open-source e-book reader tool for 64-bit and ARM64 PCs. Administrators can deploy it unattended.
Is Thorium safe to download?
- The file is served by github.com, the publisher’s own domain
- The download link uses HTTPS
- A SHA256 hash is published, so you can verify the file:
AD33003C0648B8F8F91CB9368B457701F23B1ED9443B01C94934F756F7ED98FD· Open the VirusTotal report for this hash - The link has not been checked yet
- The source code is public
- ExeAtlas does not host, wrap or modify installers
Related guide: How to check a file’s SHA256 hash on Windows
Security practices (OpenSSF Scorecard)
Automated checks of the edrlab/thorium-reader repository on GitHub by the Open Source Security Foundation, last run on October 19, 2026.
- Actively maintained10
- No dangerous workflows10
- No binaries in the repository10
- Restricted token permissions10
- Licence declared10
- Static code analysis8
- Pinned dependencies5
- Branch protection3
- Code review1
- OpenSSF Best Practices badge0
- Signed releases0
- Security policy0
- Fuzzing0
The score rates how the project is developed and released, not whether the program is safe to install. scorecard.dev
Recent versions
All 13 versions ›13 versions over 4 years · about 3.2 a year
| Version | Date | Size | Files |
|---|---|---|---|
| 3.5.1Latest | September 2, 2026 | — | 64-bit EXE (NSIS)ARM64 EXE (NSIS)ARM64 EXE (NSIS)64-bit EXE (NSIS) |
| 3.4.0 | April 9, 2026 | — | ARM64 EXE (NSIS)64-bit EXE (NSIS)64-bit EXE (NSIS)ARM64 EXE (NSIS) |
| 3.3.0 | December 9, 2025 | — | 64-bit EXE (NSIS)ARM64 EXE (NSIS)ARM64 EXE (NSIS)64-bit EXE (NSIS) |
| 3.2.2 | August 19, 2025 | — | ARM64 EXE (NSIS)64-bit EXE (NSIS)ARM64 EXE (NSIS)64-bit EXE (NSIS) |
| 3.2.1 | August 11, 2025 | — | ARM64 EXE (NSIS)64-bit EXE (NSIS)ARM64 EXE (NSIS)64-bit EXE (NSIS) |
| 3.1.0 | February 18, 2025 | — | ARM64 EXE (NSIS)ARM64 EXE (NSIS)64-bit EXE (NSIS)64-bit EXE (NSIS) |
| 3.0.0 | October 1, 2024 | — | 64-bit EXE (NSIS) |
| 2.4.2 | May 20, 2024 | — | 64-bit EXE (NSIS) |
Install from the command line
Silent install ›winget install --id EDRLab.Thorium -escoop install extras/thorium-readerThorium-3.5.1-x64.exe /SRelated guide: How to use winget: install and update apps
Also for other systems
brew install --cask thoriumInformation
- Publisher
- EDRLab
- Category
- E-book readers
- Licence
- BSD-3-Clause
- Price
- Free
- Source code
- github.com/edrlab/thorium-reader
- Written in
- TypeScript
- Requires
- Windows 11 / 10
- Architecture
- 64-bit, ARM64
- Installer
- EXE (NSIS)
- Version
- 3.5.1
- Released
- September 2, 2026
- Added to the catalogue
- September 4, 2022
- Versions listed
- 13
- Updates / year
- 3.2
- GitHub stars
- 2,912
- GitHub forks
- 242
- Website
- edrlab.org
- winget ID
- EDRLab.Thorium
- Scoop package
- extras/thorium-reader
File types it opens (9)
Ratings and reviews
No reviews yet. Be the first to rate it.
Alternatives to Thorium
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Open source1.5M ↓ -
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Frequently asked questions
Is Thorium free?
Yes. Thorium is open-source software under the BSD-3-Clause licence.
Is Thorium safe to download?
The download comes from github.com, which belongs to the publisher; ExeAtlas does not host or change the file. Compare its SHA256 hash with the one shown here, or open the VirusTotal report for that hash.
How do I install Thorium with winget?
Open PowerShell or Windows Terminal and run the winget command shown on this page. winget downloads the official installer and checks its SHA256 hash before running it.
Can Thorium be installed silently?
Yes. The silent install page lists the exact command for each installer.
Does Thorium run on ARM (Windows on Arm)?
Yes, there is a native ARM64 installer.
Where can I download an older version of Thorium?
The versions page lists all 13 versions with links to their official installer files, back to August 9, 2022.
Can I use Thorium without administrator rights?
Yes, there is a per-user installer that does not need administrator rights.
What are alternatives to Thorium?
calibre, SumatraPDF, Sigil, BlueGriffon and Kindle Comic Converter. The alternatives page compares them.
