Download Calibre 9 (64-bit) Free, an eBook management program for reading EPUBs, converting files, organizing libraries, and sending books to digital reading devices on Windows with a complete suite of editing tools.

Get to know Calibre.

Calibre is the world's most popular open-source e-book library management program, developed by Kovid Goyal, first released in 2006, and continuously developed to this day. Its key feature is being the central hub for managing all of a user's digital book collection, regardless of where they were obtained or what file format they are in. Calibre helps organize, edit book metadata, and convert files to match each individual's reading device comprehensively in one place.

Calibre's primary function is library management. Users can add books to the program individually or as entire folders. It automatically copies the files into an organized folder structure based on author and title, and automatically populates metadata from online databases like Google Books. This makes it easy to find and browse libraries with thousands of books, allowing them to be grouped by tags, series, or rating, and searched quickly using keywords.

Another important function is ebook file format conversion. Calibre supports a wide variety of import formats, including EPUB, MOBI, AZW3, PDF, TXT, HTML, DOCX, and CBZ, and can convert between formats freely. For example, it can convert EPUB to AZW3 for Kindle or convert documents for comfortable reading on small e-reader screens. Users can customize conversion details in depth, including font, font size, and margins, to ensure the resulting file is best suited to their device.

In addition, there's a built-in ebook editor for opening EPUB or AZW3 files and directly editing text, style, or cover images. It features automatic news article conversion from websites, sending them to the e-reader at a set time. There's a built-in server allowing you to read books via a browser or mobile app from anywhere. It also supports hundreds of community-generated plugins, offering virtually unlimited capabilities. For those who want to convert PDF files to page-turning ebooks, that's also available. Flip PDF Pro Designed specifically for this task.

Calibre works on Windows, macOS, and Linux, and is free to use forever with no ads or locked features. Being open-source makes it transparent, secure, and supported by a global user community. For anyone collecting a large number of e-books who wants a systematic management tool not tied to any single store, Calibre is the most comprehensive answer.

Who is this program suitable for?

People who have collected a large number of ebooks and are starting to lose track of where they want them will benefit most from Calibre. It organizes books like a real library, allowing you to search by title, author, or tags in seconds, instead of piling files in folders and forgetting which books you own.

Another group includes readers on e-readers like Kindle or Kobo who want to transfer their books to the device without going through a retailer; they can simply connect the device and transfer the files. Those with multiple file formats mixed together, such as EPUB, MOBI, AZW3, and PDF, can use a cross-format converter so they can be opened and read on any device without needing additional software.

Key Features

Library Management. Calibre enables efficient management of book collections by allowing users to add, edit, and organize book metadata such as title, author, cover, and description. Books can also be grouped by categories or tags for easier searching.
E-book conversion. This software supports converting book files into various formats such as EPUB, MOBI, AZW3, PDF, and others, making it convenient to read books on different devices. The conversion also allows for customization, such as adjusting font size and adjusting the e-book's appearance.
Device Syncing. It can connect and sync books with various e-readers such as Kindle, Nook, and Kobo, making it easy to transfer book files.
Editing and reading e-books. There are tools for reading and editing e-books. We can use Calibre to open and read e-books or use the editing tools to improve the content or format of the book.
News Downloading and Management. You can configure the system to download news from various websites and convert it into e-books for later reading. Additionally, the downloaded news is categorized for easier reading.
Multi-platform support. Calibre is compatible with multiple operating systems, including Windows, macOS, and Linux, allowing for convenient access and use regardless of the operating system used.
Data backup and restoration. Users can back up their library resources to prevent data loss and easily recover data in case of problems.
Extensions and support (Plugins and Support). It supports the installation of plugins that add various capabilities and features. We can search for and install additional plugins as needed.

eBook editing tools. Edit HTML, CSS, images, and the book's table of contents all in one program.
Content server. Access the web-based library to read or download books from devices on the network.
Search and filter. Search by name, author, tag, or metadata, and save the search query for reuse.
Supports online news. Pull news from your specified sources and automatically convert it into an eBook.

What's new

Version 9.18.0 – 06 Nov, 2026

Accessibility tools in the E-book Editor. Set the language for books and individual HTML files, fix alternative text for all images in one place—including inline SVG images—and fix EPUB accessibility metadata. The Check book feature reports images without alternative text, HTML files without a language, skipped heading levels, and missing metadata, with many issues fixable automatically.
Preview colors before editing. The E-book Editor displays colors with underlines, and you can Ctrl-click on a color to change it immediately using the color wheel.
Content server syncs reading progress with KOReader. Set up a custom sync server in KOReader pointing to the Content server, and reading positions can be shared across devices and across book formats for the same book. It also serves OPDS 2.0 feeds, streams CBZ comics while respecting manga reading directions, and searches book content from a full-text index.
New calibredb command set. Manage notes, annotations, data files, virtual libraries, and the trash can from the command line, alongside renaming and deleting tags and series.
The reader can search within the current chapter only. Limit searches to just the chapter being read, while the Content server viewer allows rating books and deleting them from downloaded books upon finishing reading.
Search with new date keywords. Use lastmonth, thisyear, lastyear, monthsago, and yearsago for date-based searches now, while EPUB Output sets the language of HTML files and uses the book title and language on generated cover pages.
Get books adds new bookstores. Fetch books from Standard Ebooks, DOAB, and DOAJ now, while calibre-debug inspects exported calibre data without restoring, and Read aloud can resume downloading pending audio and drops hanging connections.
Fixed multiple conversion issues. Improved page number detection and large image handling in PDF Input, fixed a freeze when the PDF Output rendering process stops working, fixed multiple issues in TXT, RTF, EPUB, and DOCX, and fixed errors when opening EPUB files for the first time on Windows and the creation of camoufox shortcuts every time the program opens.
Improved news recipes. News recipes for The Times and Sunday Times, Financial Times, The Boston Globe, and Hacker News have been updated to fetch news more accurately.