Calibre is a free, open-source e-book manager for converting, editing, and organizing books across Kindle, Kobo, and other devices. See features and history.
Category
Media & Audio/Video Tools
Pricing
Free (open-source), from Free
Verified
Not yet
Last updated
July 18, 2026
Founded
2006
Headquarters
Mumbai, India
Free PlanWindowsOpen SourceSelf-HostedMac
Overview
Calibre is a free, open-source e-book management application created by Kovid Goyal and first released on October 31, 2006, originally to work around the lack of Linux support for Sony's PRS-500 e-reader. It grew from a simple format converter into a full e-book library manager, renamed calibre in 2008.
Goyal, based in Mumbai, India, remains the lead developer alongside a small core team and a large volunteer community that has translated the software into more than a dozen languages. Calibre runs on Windows, macOS, and Linux.
Key Features
Calibre manages a searchable e-book library with automatic metadata and cover fetching, converts books between formats like EPUB, MOBI, AZW3, and PDF, and includes a built-in viewer and editor for adjusting fonts, margins, and tables of contents.
It syncs books to Kindle, Kobo, Nook, and other e-reader devices, can download news sources and convert them into e-books, and offers an optional self-hosted content server for remote library access.
Pricing
Calibre is completely free and open source, with no paid tiers, subscriptions, or licensing fees for any of its features.
Key Features
E-Book Library Management — Organize a personal e-book collection with searchable, editable metadata.
Format Conversion — Convert between EPUB, MOBI, AZW3, PDF, and many other e-book formats.
Built-In Viewer & Editor — Read books and edit formatting, fonts, margins, and auto-generated tables of contents.
Automatic Metadata & Covers — Fetch book metadata and cover art from the internet automatically.
Device Sync — Transfer and sync books to Kindle, Kobo, Nook, and other e-reader hardware.
News & Periodical Download — Download online news sources and convert them into e-books for offline reading.
Self-Hosted Content Server — Optional server component for remote, browser-based access to a user's library.
Plugin Architecture — Extend functionality with community-built plugins.
Pros & Cons
Pros
Completely free and open source with no paid tiers
Extremely broad e-book format support and conversion quality
Actively maintained since 2006 with regular updates
Cross-platform on Windows, macOS, and Linux
Cons
Interface is more utilitarian than modern consumer apps and has a learning curve for advanced features
No official first-party mobile app for iOS or Android
Primarily desktop-focused; remote access requires manually setting up the content server
Frequently Asked Questions
Is Calibre free?
Yes, calibre is completely free and open source with no paid tiers or subscriptions.
Who created Calibre?
Calibre was created by Kovid Goyal, who first released it on October 31, 2006, initially to add Linux support for Sony's PRS-500 e-reader.
What e-book formats does Calibre support?
Calibre supports converting between most major e-book formats, including EPUB, MOBI, AZW3, and PDF.
Does Calibre work with Kindle?
Yes, calibre can convert and sync e-books to Kindle devices, as well as Kobo, Nook, and other e-readers.
Is Calibre available on Mac and Linux?
Yes, calibre is cross-platform and runs natively on Windows, macOS, and Linux.