Free online MOBI to OGG converter

A MOBI ebook contains book text, while some audiobook players and audio workflows require an OGG audio file. Converting it means synthesizing speech from the text; it does not recover an original narration.

What the MOBI format is

MOBI is an ebook format used for digital books, especially older books made for Kindle devices and apps. You may encounter MOBI files downloaded from ebook libraries or exported from publishing and ebook-management software. The format stores book content and layout, not a spoken audio track.

What the OGG format is

OGG is a multimedia container commonly used for audio encoded with Vorbis. OGG Vorbis is lossy-compressed audio and is supported by many media players and software tools. Choose it when a player or workflow specifically accepts OGG; converting book text creates computer-generated narration.

Online on 101convert.com

1. Upload the MOBI file on the 101convert.com converter page. You can add several files for batch conversion; the page shows the per-file size limit.
2. Before converting, choose the voice language and reading speed.
3. Start the conversion, then download the resulting OGG file.

Offline with desktop software

For a local workflow, use Calibre to extract readable text, eSpeak NG to synthesize speech, and FFmpeg to encode the audio as OGG. These tools are available for Windows, macOS, and Linux.

1. Install Calibre, eSpeak NG, and FFmpeg. In a terminal or command prompt, convert the ebook to plain text with ebook-convert "book.mobi" "book.txt".
2. Generate a WAV narration with eSpeak NG; change the voice code and rate as needed: espeak-ng -v en-us -s 165 -f "book.txt" -w "speech.wav".
3. Encode the WAV as OGG Vorbis with FFmpeg: ffmpeg -i "speech.wav" -c:a libvorbis -q:a 5 "book.ogg".

Calibre cannot extract text from DRM-protected books unless the file is legitimately accessible without that protection. If the text export contains unwanted formatting or navigation, clean book.txt before generating speech.

Quality and compatibility

The synthesized voice and reading rate determine how the book sounds; the Vorbis quality setting affects the encoded audio, not the narration. OGG support varies by device, so check that the intended player accepts OGG Vorbis. MOBI files with DRM may not be readable by conversion software.