head to head · open source
koreader vs calibre
koreader has 30,818 GitHub stars, 2,019 forks, 1,345 open issues and last shipped yesterday. calibre has 26,327 stars, 2,743 forks, 6 open issues and last shipped yesterday. koreader leads on adoption by 17% (30,818 vs 26,327 stars). koreader is written in Lua under AGPL-3.0; calibre is written in Python under GPL-3.0. koreader has attracted 7% as many forks as stars, calibre 10%. koreader was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 4 topic tags (ebook, ebook-reader, epub, kindle), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
← all 20902 open source comparisons
Side by side
| koreader | calibre | |
|---|---|---|
| GitHub stars | ★ 31K | ★ 26K |
| License | AGPL-3.0 | GPL-3.0 |
| Written in | Lua | Python |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 2.0K | ⑂ 2.7K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick koreader if
- You weight community size — 31K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches Lua
- You value the larger contributor base for long-term maintenance
pick calibre if
- You want the calibre feature set and don't need the biggest community
- You prefer the GPL-3.0 license terms
- Your stack matches Python
- You evaluated both and calibre fits your workflow better
About koreader
KOReader is a document viewer primarily aimed at e ink readers. [![AGPL Licence][badge license]](COPYING) [![Latest release][badge release]][link gh releases] [![Gitter][badge gitter]][link gitter] [![Mobileread][badge mobileread]][link forum] [![Build Status][badge circleci]][link circleci] [![Coverage Status][badge coverage]][link coverage] [![Weblate Status][badge weblate]][link weblate] Download • User guide • Wiki • Developer docs Main features portable : runs on embedded devices (Cervantes, Kindle, Kobo, PocketBook, reMarkable), Android and Linux computers. Developers can run a KOReader emulator in Linux…
read the full koreader overview →
About calibre
calibre calibre is an e book manager. It can view, convert, edit and catalog e books in all of the major e book formats. It can also talk to e book reader devices. It can go out to the internet and fetch metadata for your books. It can download newspapers and convert them into e books for convenient reading. It is cross platform, running on Linux, Windows and macOS. For more information, see the calibre About page. Screenshots Screenshots page Usage See the User Manual. Development Setting up a development environment for calibre. A tarball of the source code for the current calibre release. Bugs Bug reports and…
read the full calibre overview →
More in Content & Publishing
Related comparisons
More Publishing projects
Compare either of these against the rest of the Publishing field.
Frequently asked questions
Is koreader or calibre more popular?
koreader has 30,818 GitHub stars and calibre has 26,327. koreader has the larger community by that measure.
Are koreader and calibre free?
Both are open source. koreader is licensed under AGPL-3.0 and calibre under GPL-3.0. Neither carries a licence fee.
What is the difference between koreader and calibre?
koreader is written in Lua and calibre in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, koreader or calibre?
Choose koreader if you want the larger community (30,818 stars) or its AGPL-3.0 licence terms. Choose calibre if its feature set, stack or GPL-3.0 licence fits better. Both are self-hostable.