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calibre

calibre is an e-book manager, converter, viewer and editor created and maintained by Kovid Goyal. It is free and open-source software distributed under the GNU General Public License version 3.

Licensing at a Glance

  • Open source

  1. The calibre project describes calibre as completely free and open source.[1]

  2. The calibre source repository is distributed under the GNU General Public License, version 3.[2]

  3. The calibre COPYRIGHT file lists Kovid Goyal as copyright holder for the code base under GPL-3, with some bundled components under other licences such as MIT, SIL OFL and BSD.[3]

  4. calibre is offered for Windows, macOS and Linux, plus a portable build.[4]

  5. The calibre website invites voluntary contributions and patronage to support its development.[5]

Products

References

  1. calibre - About · calibre-ebook.com · retrieved 2026-09-27
  2. calibre/LICENSE · github.com · retrieved 2026-09-27
  3. calibre/COPYRIGHT · github.com · retrieved 2026-09-27
  4. calibre - Download calibre · calibre-ebook.com · retrieved 2026-09-27
  5. calibre - E-book management · calibre-ebook.com · retrieved 2026-09-27
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