[GUI Plugin] Argos Translate - offline ebook translation (50 languages)

[zermok]

Argos Translate

Translate EPUB and AZW3 books entirely offline between 50 languages, with Argos Translate. No account, no API key, and the text of your books never leaves your computer. Works from calibre's toolbar and from the command line.

Features

• Two modes: Replace (a fully translated book) or Bilingual (each paragraph followed by its translation, handy for language learners)
• The book stays intact: it is edited in place with calibre's own book-editing engine, not converted. Structure, CSS, images, links and footnotes are kept; the table of contents and language metadata are updated
• No setup: the first translation installs what it needs automatically (uv, Python 3.12, argostranslate, the language model)
• Any pair between the 50 Argos languages, going through English when there is no direct model
• Resumable: translations are cached, so an interrupted job continues where it stopped
• Batch: translate many books at once from the GUI, or whole folders from the command line
• CPU or CUDA

Requirements

• calibre 6.0 or later, on Windows, macOS or Linux
• Internet access for the first run (to download the translation engine and each language model once). After that, translation works offline
• Disk space: several hundred MB to a few GB for the engine, plus roughly 100 MB per language model

Installation
Preferences > Plugins > Get new plugins and search for Argos Translate, or Load plugin from file with the zip attached to this post. Restart calibre, then add the Translate button via Preferences > Toolbars & menus if calibre didn't place it.

Usage
Select one or more books with an EPUB or AZW3 format, click Translate, choose the source language (or "Book language" to use the metadata), the target language and the mode. Each book runs as a background job in the Jobs list; the result is added as a new book, e.g. Title [fr].

The first job sets up the translation engine, so it takes a few minutes. Missing language models are downloaded the first time a job needs them; this can be turned off in the plugin settings for strictly offline use.

Command line

calibre-debug -r "Argos Translate" -- "book.epub" -t fr
calibre-debug -r "Argos Translate" -- book.epub -t es -m bilingual
calibre-debug -r "Argos Translate" -- ./library -r -t fr --output-dir ./translated
calibre-debug -r "Argos Translate" -- --list

Run with -h for all options. Folders are translated as a batch, books already translated are skipped, and output paths are printed so the command is easy to script. Full documentation: GitHub README.

Known limitations

• Italic/bold words inside a sentence lose that formatting in the translation
• EPUB and AZW3 only: convert other formats first
• Machine translation quality depends on the Argos model; pairs going through English are weaker

Troubleshooting
Error messages include the end of the translation worker's log. For errors inside calibre itself, start it with calibre-debug -g and post the terminal output in this thread.

Source and license
github.com/ROBERT-MCDOWELL/argostranslate-calibre-plugin, MIT license.

Version History

Spoiler:

Version 26.10.1 - 5 Oct 2026
Initial release