calibre
Freecalibre is a free, open-source e-book manager that converts, edits, organises and syncs e-books.
About calibre
calibre is a free, open-source e-book manager for Windows, macOS and Linux. It can view, convert, edit and catalogue e-books in all major formats, and it keeps a searchable library with metadata and covers.
Its best-known feature is format conversion, for example from EPUB to MOBI or PDF, and it can also send books to many e-reader devices, fetch metadata and news, and run a content server to read your library over the network. The recent 9.15 release notes mention an optional AI-based writing game and viewer highlight improvements. Plugins extend it further, adding features from metadata sources to extra conversion tools, and the project has a long release history with frequent updates. It is a power tool, so beginners may start with its basic import and convert functions.
It suits anyone with a personal e-book collection, especially those using non-Amazon readers. The software is free under GPL-3.0 and run by lead developer Kovid Goyal. The interface is dense and utilitarian, so give yourself a little time to learn it. AI features are optional and are not loaded unless you run them.
Removing DRM is not built in and may be unlawful in your country, so use it for books you can legally convert. Back up the library folder.
Version history
1 release tracked- Windows: New optional AI Create your own adventure writing game
- E-book viewer highlights panel allows multi-select
- Cover grid emblem corner option
Frequently asked
Is calibre free?
Yes. It is free software released under the GPL-3.0 license.
Does it need an account?
No. It runs locally with no sign-up.
Which platforms does it run on?
Windows, macOS and Linux.
Where does the download link go?
Directly to calibre-ebook.com or the official app store for your platform. PlanetSofts never rehosts installers or adds wrappers, and these links were last verified Oct 6, 2026.