Best Free Ebook Readers 2026: 6 Options Compared
Best free Ebook Readers compared: calibre, Koodo Reader, Readest, Foliate and 2 more, with free-plan limits, platforms and prices from official pages checked October 24, 2026.
•3 min read•Learning & Everyday Apps
Quick comparison
| Tool | Price | Platforms | Best for | Tested |
|---|---|---|---|---|
| calibre | Free (Free and open source e-book manager and converter) | Desktop | Managing and converting a big library | Docs only |
| Koodo Reader | Free (Source code is AGPL-3.0; the project also sells a Pro version whose price was not checked) | Windows, macOS, Linux, Web browser, Android, iOS | One reader on every device | Docs only |
| Readest | Free (The reader's source code is AGPL-3.0; the project also offers a hosted sync service whose terms were not checked) | Windows, macOS, Linux, Android, iOS, Web browser | Modern interface with sync | Docs only |
| Foliate | Free (Free open-source GTK ebook reader for Linux) | Linux | Reading EPUB on Linux | Docs only |
| SumatraPDF | Free (Free with no ads, bundled software or subscription; a portable version runs without installing) | Windows | Fast PDF and EPUB on Windows | Docs only |
| Kindle app | Free (Free app; Kindle books you bought on Amazon appear in it, and Kindle Unlimited or Prime titles can be downloaded) | iOS, Android, Mac | Reading books bought from Amazon | Docs only |
Independent comparison. Paid placements are labelled separately; editorial links earn no affiliate commissions. Learn more.
Good fit if
- You own hundreds of books in mixed formats (calibre is the pick)
- You want one app on phone, desktop and web (Koodo Reader is the pick)
- You read PDFs and EPUBs on an old Windows PC (SumatraPDF is the pick)
- You buy from Amazon (Kindle app is the pick)
Not ideal if
- You need paid-tier features, uptime guarantees or support that these free plans leave out
A free ebook reader should match your file formats and devices. calibre is the toolbox: it manages a large library, converts between formats, and edits metadata, though its reader is plain. Koodo Reader and Readest are modern open-source readers (both AGPL-3.0) with sync features; Koodo supports over 15 formats and apps on Windows, macOS, Linux, Android, iOS and the web, and both projects also offer paid extras, so read what the free build includes. Foliate is a clean GTK4 reader for Linux desktops. SumatraPDF is a tiny, ad-free Windows reader that opens PDF, EPUB and comic files fast but has no library or sync. The Kindle app is free on iPhone, iPad and Mac, and shows books you bought from Amazon plus Kindle Unlimited and Prime titles, but it locks you into Amazon's format. The trade-off is openness versus store convenience: open readers read EPUB and files you own, but they do not buy books for you, whereas the Kindle app buys easily but ties your library to one company. If you want to move books between devices, calibre plus an open reader gives you the least lock-in. Check DRM: protected files will not open in open-source apps.
calibre
GPL-3.0 library manager and converter for Windows, macOS and Linux. Powerful for organising and converting, but its built-in reader and interface are utilitarian.
Price: Free (Free and open source e-book manager and converter) (calibre pricing, checked 2026-10-24).
Platforms and license: Desktop. GPL-3.0 (open source).
Project activity: 26.3k GitHub stars · latest release v9.17.0 (Oct 23, 2026) · last commit Oct 27, 2026
Best for: Managing and converting a big library.
Worth knowing: Whether a given PDF converts cleanly was not tested. License taken from the repository metadata and LICENSE file; description from the project README. No paid plan was checked.
Koodo Reader
AGPL-3.0 reader with over 15 formats and apps on six platforms. A Pro version exists; check the site for which features it adds.
Price: Free (Source code is AGPL-3.0; the project also sells a Pro version whose price was not checked) (Koodo Reader pricing, checked 2026-10-24).
Platforms and license: Windows, macOS, Linux, Web browser, Android, iOS. AGPL-3.0 (open source).
Project activity: 28.6k GitHub stars · latest release v2.4.6 (Oct 7, 2026) · last commit Oct 27, 2026
Best for: One reader on every device.
Readest
AGPL-3.0 reader for desktop, mobile and web. A hosted sync service is offered and its terms were not checked.
Price: Free (The reader's source code is AGPL-3.0; the project also offers a hosted sync service whose terms were not checked) (Readest pricing, checked 2026-10-24).
Platforms and license: Windows, macOS, Linux, Android, iOS, Web browser. AGPL-3.0 (open source).
Project activity: 25.7k GitHub stars · latest release v0.12.16 (Oct 13, 2026) · last commit Oct 27, 2026
Best for: Modern interface with sync.
Foliate
GPL-3.0 GTK4 ebook reader with a clean, distraction-free layout. It is built for Linux desktops only, so it will not help on Windows or Mac.
Price: Free (Free open-source GTK ebook reader for Linux) (Foliate pricing, checked 2026-10-24).
Platforms and license: Linux. GPL-3.0 (open source).
Project activity: 8.8k GitHub stars · latest release 3.3.0 (Apr 1, 2025) · last commit Apr 8, 2026
Best for: Reading EPUB on Linux.
Worth knowing: License verified from the repository LICENSE/COPYING file on GitHub on 2026-10-24; platforms listed from project knowledge, not re-verified on the project site.
SumatraPDF
Free Windows reader with no ads, bundled software or subscription; a portable version needs no install. No library management or sync.
Price: Free (Free with no ads, bundled software or subscription; a portable version runs without installing) (SumatraPDF pricing, checked 2026-10-23).
Platforms and license: Windows. Open source (license not named on the page) (open source).
Project activity: 17.9k GitHub stars · latest release 3.6.1rel (Apr 6, 2026) · last commit Oct 28, 2026
Best for: Fast PDF and EPUB on Windows.
Worth knowing: Windows only (7 to 11, 32-bit, 64-bit and ARM64). Reads PDF, EPUB, MOBI, CBZ, CBR, DjVu, XPS, CHM and images. No paid tier mentioned.
Kindle app
Free app for iPhone, iPad and Mac showing Kindle books you bought on Amazon and Kindle Unlimited or Prime titles. Tied to Amazon's store.
Price: Free (Free app; Kindle books you bought on Amazon appear in it, and Kindle Unlimited or Prime titles can be downloaded) (Kindle app pricing, checked 2026-10-24).
Platforms and license: iOS, Android, Mac. Proprietary.
Best for: Reading books bought from Amazon.
Which one to pick
- You own hundreds of books in mixed formats: calibre
- You want one app on phone, desktop and web: Koodo Reader
- You read PDFs and EPUBs on an old Windows PC: SumatraPDF
- You buy from Amazon: Kindle app
Limits of this review
Docs-only for calibre, Koodo Reader, Readest, Foliate, SumatraPDF, Kindle app: we did not install or run them, so feature claims come from vendor pages. Vendor prices and free limits change; confirm on the linked pricing page before you commit.
Related guides
Sources
Kevin Fan
Kevin Fan is a SaaS founder. He runs Free Instead Of, which tracks free and open-source alternatives to paid software and checks each price and free-plan limit against the vendor's own pages.
Methodology
Based on official pricing, license and product pages checked between 2026-10-23 and 2026-10-24: calibre, Koodo Reader, Readest, Foliate, SumatraPDF, Kindle app. Prices, free limits and licenses are the figures shown on those pages on those dates. No tool on this page was installed or run. No accounts were created.