Calibre

Open-source ebook library manager and converter

★ Stars26.2k26,187 on GitHub

Last committoday19 Oct 2026

LicenceGPL-3.0SPDX, from the repository

View on GitHub ↗

From GitHub, fetched 19 Oct 2026.

Visit calibre-ebook.com ↗

Calibre is a free ebook management suite: convert between EPUB, MOBI, AZW3 and more, edit metadata, and run a personal content server. Indie authors use it heavily for ebook conversion.

Free alternative to

In collections

Details

Status	Open source
Licence	GPL-3.0
Platforms	Windows, macOS, Linux
Category	Formatting & publishing
Website	calibre-ebook.com
Source	GitHub

Is this your tool?

Make Calibre the Top Pick on “Vellum alternatives”: the first card people see there, labelled as sponsored. £39/month.

Book a Top Pick spot

Related tools

Pandoc

Formatting & publishing

Universal document converter for manuscripts and ebooks

Stars: ★ 46.6k
Licence: GPL-2.0
Updated: today

Alternative to Vellum, Atticus

Sigil

Formatting & publishing

WYSIWYG and code-view EPUB ebook editor

Stars: ★ 7k
Licence: GPL-3.0
Updated: 3 days ago

Alternative to Vellum, Atticus

Kindle Create

Formatting & publishing

Amazon's free formatter for Kindle and paperback interiors

Licence: Freeware
Status: Free (proprietary)

Alternative to Vellum, Atticus

Scribus

Formatting & publishing

Open-source desktop publishing for print layouts

Stars: ★ 640
Licence: GPL-2.0
Updated: yesterday

Alternative to Adobe InDesign, Vellum

Atticus

Formatting & publishing

Writing plus ebook and print formatting in one paid app

Licence: Proprietary
Status: Proprietary

Alternative to Vellum, Scrivener

Reedsy Book Editor

Novel & long-form writing

Free browser manuscript editor from Reedsy with clean export

Licence: Proprietary
Status: Freemium

Alternative to Scrivener, Microsoft Word