calibre
A cross-platform open-source ebook manager for libraries, metadata, format conversion, reading, editing, device transfer and a personal content server.
What calibre is for
calibre manages a personal ebook library, including titles, authors, series, tags and covers. It can convert between compatible unencrypted formats, edit EPUB files, send books to devices and expose a personal content server. Complex layouts, publication-grade EPUB work and protected files require a separate workflow.
Treat the library as a database
A calibre library is not just a loose folder. The metadata database, managed directories and configuration determine how books and records relate to each other. Back up the complete library and test a copy before bulk conversion, metadata cleanup or a plugin change.
Conversion and server boundaries
Conversion may change fonts, page breaks, tables, images and navigation. Open the output on the target reader and inspect a long chapter instead of trusting a successful task. If the content server is exposed beyond the local machine, configure authentication, HTTPS and access restrictions before sharing it.
Maintenance note
This page reviews calibre 9.12.0, platform packages, library backups, format conversion, device transfer, content server and plugin boundaries. Content review date: 2026-08-23.
Save to your cloud drive
Open the cloud drive to get the file directly, or save it for convenient access on another device.
Quark Cloud Drive
RecommendedSave calibre to this cloud drive
Baidu Netdisk
Save calibre to this cloud drive
calibre 9.12.0 installation and ebook library workflow
Create a test library, import a small set of unprotected books, normalize metadata, convert one sample and verify the result on the target reader before a bulk operation.
Before you start
- Select the Windows, macOS or Linux package that matches the supported system and architecture.
- Prepare a complete library backup and a separate test copy for conversion and metadata experiments.
- Confirm that the books are unencrypted or that you have the required rights for the intended operation.
Installation steps
- 01
Install the matching build
Install calibre for the operating system, start it once and choose a library directory with enough space for source files, converted copies and backups.
- 02
Create a test library
Import a small set of representative books, check the title, author, series, tags and cover fields, and keep the original files outside the managed library as a backup.
- 03
Review settings and plugins
Check conversion defaults, device profiles and plugin permissions. Add only plugins that are needed and test them against the copy of the library.
Quick start
- 01
Normalize metadata
Correct one field at a time, inspect series and author sorting, and confirm that metadata changes are reflected in the library database and book files as intended.
- 02
Convert a representative book
Choose a target format, inspect fonts, images, table of contents and page breaks, then open the result on the target reader before converting a collection.
- 03
Transfer and verify
Send the tested file to a device or local reader, compare the title and cover, and preserve the source and converted files with a record of the settings.
Usage tips
- Do not treat a successful conversion job as proof of visual quality; inspect long chapters, tables and images on the target device.
- Plugins, templates and ebook parsers can process local files, so review their source and permissions before adding them.
- The content server is a personal service, not a public file host. Restrict access and stop it when it is not needed.
Troubleshooting and uninstall
Why is a converted ebook layout broken?
Compare the source format, target profile, embedded fonts, image sizes, CSS and table of contents. Try a small sample and adjust one conversion option at a time.
Why did a device receive the wrong metadata?
Check the library record, filename template, device driver and cached cover, then reconnect with one test book before sending the whole library.
- Back up the complete libraryConfirm that metadata.db, managed book directories, configuration and recent conversion outputs are all included in a restorable copy.
- Stop the server and uninstallStop the content server, revoke external access and uninstall the application. The library usually remains on disk, so decide separately whether it should be retained.
Frequently asked questions
Does calibre remove ebook DRM?
calibre does not provide DRM removal. Work with unencrypted files or files for which the intended conversion is permitted, and check the terms that apply to the content.
Can the calibre library be moved by copying one book folder?
A library also depends on its metadata database and configuration. Back up the complete library and test the copy before removing the original.
Is the content server safe to expose publicly?
Treat it as a private service. Use authentication, HTTPS and network restrictions, and do not expose it directly without reviewing the account and access model.