There are some books with mobi and azw3 formats on my calibre library which I want to convert them to epub and I prefer to do it from command line.

I'm able to convert books using ebook-convert but I don't know how to add epub book to calibre.

calibredb add doesn't work since it considers the epub as duplicate which is true. But I want to see if there is a way to add the book as a new format to calibre library before messing with calibre sqlite db.

I have:

  • book id
  • epub path

I want:
- to add the epub to an existing entry

1 Answer 1


Old question but still unanswered, so here is my € 0,02:

Use calibredb add_format [options] id ebook_file

Blockquote Add the e-book in ebook_file to the available formats for the logical book identified by id. You can get id by using the search command. If the format already exists, it is replaced, unless the do not replace option is specified.

source: https://manual.calibre-ebook.com/generated/en/calibredb.html#add-format

So it should be as easy as calibredb add format epub $ID $epubfile

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