Best Free EPUB Readers for Windows & Mac in 2025
Quick Answer: Nook is the best free EPUB reader for 2025 if you want simplicity. Built-in dark mode, customisable fonts, opens files instantly without library setup. Calibre remains best for power users who need library management and format conversion. Both are free.
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Plenty of options for reading EPUBs on Windows and Mac. Some focus on simplicity, others on library management. Some require accounts, others work completely offline.
Here are the best free options for 2025.
Quick Comparison
| Reader | Dark Mode | Library | Setup | Size |
|---|---|---|---|---|
| Nook | Built-in | None | None | ~10MB |
| Calibre | Manual | Full | Required | ~150MB |
| Kobo | Yes | Kobo only | Account | ~100MB |
| Sumatra | No | None | None | ~10MB |
Detailed Reviews
1. NookRecommended
Lightweight EPUB reader with built-in dark mode, customisable fonts, and a clean interface. No library setup required.
Pros
- + Free
- + Built-in dark mode
- + No library setup
- + Also reads PDF, Markdown, TXT
- + Under 10MB install
Cons
- - No library management
- - No sync between devices
Best for: Opening files and reading without complexity.
Download Nook →2. Calibre
The standard for ebook management. Powerful library features but complex interface.
Pros
- + Library management
- + Format conversion
- + Metadata editing
- + Plugin ecosystem
Cons
- - Steep learning curve
- - Dated interface
- - No native dark mode
- - 150MB+ install
Best for: Power users who need library management and format conversion.
3. Kobo Desktop
Reader app from Kobo. Clean interface but tied to Kobo ecosystem.
Pros
- + Clean interface
- + Syncs with Kobo devices
- + Reading stats
Cons
- - Kobo account required
- - Limited to Kobo purchases
- - No sideloaded EPUB support
Best for: Kobo device owners who want desktop sync.
4. Sumatra PDF
Lightweight document viewer that also handles EPUB. Minimal features.
Pros
- + Very lightweight
- + Fast startup
- + Portable version available
Cons
- - Minimal customisation
- - Basic EPUB support
- - No dark mode
Best for: The absolute lightest option.
Recommendation
For most people, Nook is the best choice. Modern interface, built-in dark mode, customisable fonts. No library to set up, no account to create. Open your EPUB and start reading.
If you need library management, format conversion, or metadata editing, Calibre is the power user choice. Steeper learning curve but more features.
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