# kovidgoyal/calibre

The official source code repository for the calibre ebook manager

Repository: https://github.com/kovidgoyal/calibre
Canonical: https://ross.abutalabs.com/products/calibre
Homepage: https://calibre-ebook.com
Language: Python
License: GPL-3.0
License Family: copyleft
Topics: ebook-manager, calibre, python, ebook, ebooks, ebook-reader, ebook-formats, epub, kindle, epub-generation
Last push: 2026-08-26T16:36:43+00:00

## Health v2 (maintenance only)
Score: 98/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 96, longevity 100
- inputs: {"age_days": 4845, "days_push": 7, "days_rel": 27, "gap_med": 13.0, "n_releases_24m": 49}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 25734, forks 2657 (observed 2026-08-28T04:11:38.618017+00:00)

## What it is
calibre is a free, open-source, cross-platform e-book management application written in Python. It can view, convert, edit, and catalog e-books in all major formats, sync with e-reader devices, fetch metadata online, and download news as e-books.

## Use cases
- manage a large personal ebook library with tags and metadata
- convert epub to kindle mobi or azw3 format
- transfer ebooks to my e-reader device over usb or wireless
- edit epub files and fix metadata or covers
- download news articles and convert them into an ebook
- read ebooks on my computer with a built-in viewer
- fetch book metadata and covers automatically from the internet

## When to choose
- you need a comprehensive desktop tool to organize, convert, and sync an ebook collection
- you want format conversion between epub, mobi, azw3, pdf and other ebook formats
- you need to manage and transfer books to many different e-reader devices
- you want a free, open-source, actively maintained ebook manager

## When to avoid
- you only need a lightweight mobile or web-based reading app without library management
- you need DRM-protected ebook handling, which calibre does not support
- you want a server-first multi-user ebook streaming service rather than a desktop application

## Facets
- artifact type: application
- maturity: stable
- function: gui, file-system, templating, http-server, pdf, internationalization
- domain: files, pdf, cross-platform, developer-tools, media
- platform: windows, cross-platform, python
- tags: ebook-manager, ebook-conversion, ebook-reader, epub, kindle, library-catalog, metadata-fetching, news-download, linux, macos, desktop

## Member repositories
- kovidgoyal/calibre (main) score 98

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:11:38.618017+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T16:55:59.723229+00:00, confidence not recorded.
  - readme: https://github.com/kovidgoyal/calibre (fetched 2026-08-28T04:11:38.618017+00:00, sha 222de55e3cce)
  - homepage: https://calibre-ebook.com (fetched 2026-08-29T07:52:36.903999+00:00, sha 28d76c002687)
  - site_page: https://calibre-ebook.com/about (fetched 2026-08-29T07:52:36.906702+00:00, sha a5fe6e808f70)
- Data as of 2026-08-30T08:39:29.467469+00:00.