Calibre Ebook Library, De-DRM, Conversion

Updated 28-Jun-2024

Calibre is an ebook management tool. It is open source and cross-platform, and has been around for a long time. This explains the rather dated interface. While it is ugly, it works fairly well, and there is nothing that competes.

Calibre Functionality

Calibre calls itself an ebook management tool, but really any digital document can be stored in it.

Document Files in Folders

It organizes files in folders based on the author(s) name(s), and subfolders based on the title name. When renaming the author or title, the file folders are renamed as well. It keeps a metadata file as well as a book cover image (if available) and then one file each for one or more filetypes (e.g., epub, pdf, azw, mobi, etc.).

Install Calibre

For Debian Test can download usually the second most-recent version. For the most recent have to download the .deb from the website.

sudo apt install calibre


Removing DRM from Kindle is important so that one has access to what one has purchased. It only makes sense. I realize the importance of DRM, but as a consumer it is unacceptable (if avoidable). Therefore, there is a De-DRM plugin for Calibre which along with the KFX Input plugin (found in plugins) makes short work of the DRM.

Over the years there was a back-and-forth of changing encryption and improved decryption tools. Things are pretty solidly in favor of De-DRM these days, though on the Apple/OSX/iOS platform the use of Fairplay makes decryption difficult.

Configuring Calibre to strip out encryption from Kindle ebooks

This consists of installing and configuring two plugins. Unfortunately since the introduction of KFX, it also means manually downloading Kindle ebooks from the Amazon website, and then importing into Calibre, and then sideloading into the Kindle device, as such:

Note that this does require one to have a registered Kindle device, otherwise download is not an option on the menu.

Decryption Plugins for Calibre

  • DeDRM tool
    • Download and install the zip file
    • Configure with the Kindle serial number
  • KFX Input plugin can be installed from within Calibre plugin area

Epub Merge plugin

Install from within the Calibre plugins location (it can be found by searching for epubmerge). Works very well when dealing with CBR/CBZ comics that are imported using the Kindle Comic Converter.

CBR / CBZ to Epub Kindle Comic Converter

A great tool, can drag and drop. Settings for the Kindle Paperwhite 1 (to not have additional whitespace) is:

- Other
- Manga
- 738 x 928 px (suitable for Kindle Paperwhite v.1-4)
- Epub

Upon conversion, can group epubs together via the epubmerge Calibre plugin.

Steps to convert and merge using KCC

  • Open up KCC
  • Configure settings (as above)
  • Drag initial set of CBR / CBZ files into KCC
  • Convert to Epub
  • Edit first Epub file to remove any unnecessary initial pages or images
  • Delete Cover page if not desirable (will use first image in book as cover page thereafter)
  • Import Epub or Epubs into Calibre
  • If merging is desirable, select Epubs and click EpubMerge button in Calibre, providing appropriate title metadata
  • If having merged, then delete the original Epubs that were merged from Calibre, leaving behind only the merged file

Other Resources