Calibre eBook Manager

Calibre is a powerful and easy-to-use open-source e-book manager, designed to help users organize, convert, edit, and read their e-book collections. Created by Kovid Goyal in 2006, Calibre has over 19,000 stars as of 2026 and is the most popular e-book management software, with millions of downloads and a vibrant community of contributors and plugin developers. Key features include: library management (organizing thousands of e-books with metadata editing, tags, custom columns, ratings, and comments, with virtual libraries for filtered views), format conversion (converting between e-book formats including EPUB, MOBI, AZW3, PDF, DOCX, TXT, RTF, HTML, LRF, PDB, and CBZ with customizable conversion settings for fonts, layout, margins, and metadata), e-book editing (visual EPUB and AZW3 editor for direct modification of book content, stylesheets, and metadata with table of contents generation), device integration (syncing with Kindle, Kobo, Nook, Sony, PocketBook, and Android e-reader devices via USB or wireless, with automatic format conversion during transfer), news fetching (downloading news articles from over 1,500 news sources including BBC, New York Times, Economist, and custom RSS feeds, converting them to e-book format for offline reading), content server (web-based library access enabling browsing, searching, and downloading e-books from any device on the network via browser), OPDS catalog (publishing the library as an OPDS feed for integration with mobile e-reader apps), e-book viewer (built-in viewer supporting EPUB, MOBI, AZW3, PDF, CBZ, CBR, and PDB with bookmarking, highlighting, and dictionary lookup), metadata download (fetching book metadata, covers, and reviews from Amazon, Google Books, and Big Book Search), plugins (over 300 community plugins extending functionality for DRM removal, metadata enhancement, format-specific tools, and workflow automation), and cross-platform (Windows, macOS, Linux with portable versions).