Is Calibre free to download and use?

Yes, Calibre is completely free and open source, licensed under the GPL. You can download it, use it for any purpose, and even modify the source code.

Do I need an internet connection to use Calibre?

Calibre is a local application that runs entirely on your computer. It does not require an internet connection to manage your library, except for specific features like fetching news from the web or syncing with cloud-based readers.

What are the system requirements for Calibre?

Calibre is compatible with Windows 10 and later (64-bit), macOS 10.14 Mojave and later, and Linux (various distributions including Ubuntu, Fedora, and Arch). It requires at least 2 GB of RAM and 150 MB of disk space.

Calibre

Calibre 9.17.0 – Easily Manage E-books

Kalsoom Tahir
October 25, 2026
Tools (category)

Download Calibre, the free and open-source e-book manager for Windows, macOS, and Linux. Organize, convert, sync, and read your entire e-book library with ease