What is KOReader, and should you install it?
KOReader is a free, open-source reading app that runs on almost every e-reader. Here is what it does, what it does not, and who it is for.
Last updated August 2026
KOReader is a free reading application maintained by volunteers. It runs on Kobo, Kindle, PocketBook, BOOX and several other devices, sitting alongside — or instead of — the software your reader shipped with.
Why people install it
- Typography control. Fine-grained margins, line spacing, hyphenation and embedded-font handling that stock readers rarely expose.
- One reading experience everywhere. The same app, settings and shortcuts on every device you own.
- Format range. EPUB, PDF, CBZ, FB2, DjVu and more, with a genuinely usable PDF reflow mode.
- Statistics and sync. Reading-time tracking and progress sync across devices without an account tied to a store.
Why you might not
- The interface is dense and takes an afternoon to learn.
- On locked-down devices (most Kindles) installing it is fiddly and can be undone by firmware updates.
- If the stock reader already does what you need, KOReader is optional, not mandatory.
The short version
If you like adjusting how a page looks, or you own more than one reader, KOReader is worth the setup time. If you just want to open a book and read, the stock software is probably fine.