# epub2audiobook

> Free EPUB to audiobook converter. The narration is generated inside your browser, so your book stays on your computer. Get a chaptered M4B or one MP3 per chapter. No account, no copies kept.

epub2audiobook turns an EPUB ebook into a spoken audiobook. The narration is
generated by a neural text-to-speech model running as WebAssembly inside the
visitor's own browser: the file is read from local disk, parsed into chapters,
normalised for speech, synthesised a sentence at a time and encoded to an
audiobook in memory. There is no upload endpoint, no server-side processing and
no storage. The site is static.

## Key facts

- Input: EPUB 2 or EPUB 3, up to 60 MB. DRM-protected books are detected and
  refused, because the encryption cannot be read and should not be.
- Output: M4B with chapter marks and cover art (the default), a zip of one MP3
  per chapter, or a zip of uncompressed WAVs.
- Speech: Piper, a VITS model of about 63 MB, run through ONNX Runtime compiled
  to WebAssembly. No graphics card is required or used.
- Speed: roughly ten times faster than real time on an ordinary CPU, so a
  ten-hour book takes about an hour. The machine is measured on a few paragraphs
  before any estimate is shown.
- Voices: 11, covering American, British and Scottish English in
  both male and female. Piper publishes no Australian English voice, and Scottish
  is female only.
- Chapters come from the book's own navigation document or NCX. Where a table of
  contents wraps everything in one section, the level beneath it is used, so an
  anthology does not become a single four-hour chapter.
- Front matter is stripped: page numbers, running heads, footnote markers and
  note bodies, and Project Gutenberg's header, transcriber's notes and licence.
- Image-only EPUBs are detected and refused. There is no OCR.
- A conversion can be closed and resumed. Progress is checkpointed to the
  browser's origin-private filesystem, and re-picking the same file continues
  from where it stopped.
- No accounts, no cookies, no analytics, no third-party requests of any kind.
  The only network traffic after the page loads is fetching the voice model.

## Pages

- [Converter](https://epub2audiobook.com/): the tool itself.
- [EPUB to M4B](https://epub2audiobook.com/epub-to-m4b): chapter marks, cover art, position memory.
- [EPUB to MP3](https://epub2audiobook.com/epub-to-mp3): one tagged file per chapter.
- [EPUB to audiobook for iPhone](https://epub2audiobook.com/epub-to-audiobook-for-iphone): getting an M4B into Apple Books.
- [EPUB to audiobook for Android](https://epub2audiobook.com/epub-to-audiobook-for-android): Smart AudioBook Player, BookPlayer, Plex.
- [Listen to an EPUB](https://epub2audiobook.com/listen-to-epub): what having a book read aloud actually sounds like.
- [How it works](https://epub2audiobook.com/how-it-works): the pipeline, and its known limits.
- [FAQ](https://epub2audiobook.com/faq)
- [Privacy](https://epub2audiobook.com/privacy): why no upload happens, and how to verify it.
- [Terms](https://epub2audiobook.com/terms)

## Guides

- [Where to find EPUBs you can actually convert](https://epub2audiobook.com/guides/where-to-find-drm-free-ebooks): DRM is the one thing that stops a book being read aloud. Which shops sell files without it, which libraries lend them, and how to tell before you buy.
- [Converting in the browser or on a server: what the trade actually is](https://epub2audiobook.com/guides/browser-or-server-conversion): Upload-based converters are faster and it is not close. Here is what you give up for that speed, and when it is worth giving up.
- [M4B or MP3: which audiobook format to pick](https://epub2audiobook.com/guides/m4b-vs-mp3-audiobooks): The practical difference between a chaptered M4B and a folder of MP3s, and which one your player actually wants.
- [Audiobook players that handle chapters properly](https://epub2audiobook.com/guides/best-audiobook-players): Which apps read M4B chapters, keep your position and behave well with a self-made audiobook, on iPhone, Android, desktop and media servers.
- [Choosing a narration voice, and what to expect from it](https://epub2audiobook.com/guides/choosing-a-narration-voice): How synthetic narration actually sounds over a full book, which voice to pick, and where a human narrator is still worth paying for.