M4B Converter
Convert M4B audio files to MP3, WAV, OGG, FLAC, M4A and AAC and 8 more formats — free, in batches, files up to 10 GB, with no sign-up and no watermark.
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Free · Unlimited · No sign-up · Max 10 GB
Your privacy is our mission. Most files are converted right in your browser and never leave your device. Only large files, or formats a browser cannot process, are sent to our server over an encrypted connection — they are never stored, never shared, and deleted as soon as your download is ready.
What Is an M4B File?
M4B is an M4A file marked as an audiobook: it remembers where you stopped and can carry chapter markers. Apple Books and most audiobook apps use it. M4B is a lossy format: it makes files small by discarding detail that is hard to notice. Converting it to another format cannot bring that detail back.
M4B Facts
| Full name | MPEG-4 Audiobook |
|---|---|
| File extension | .m4b |
| Type | Audio |
| How it stores data | Lossy compression (AAC) with chapters |
| Created by | Apple |
| Best for | audiobooks |
| Watch out | music players treat it as a book, not as a song |
| Opens with | Apple Books, VLC, most audiobook apps |
How to Open an M4B File
A .m4b file opens with Apple Books, VLC, most audiobook apps. If none of those is at hand — or the file has to go into a program, device or website that refuses M4B — convert it: MP3, WAV and OGG are the usual choices.
Convert M4B to Another Format
Frequently Asked Questions
What is an M4B file?
M4B is an M4A file marked as an audiobook: it remembers where you stopped and can carry chapter markers. Apple Books and most audiobook apps use it.
How do I open a .m4b file?
With Apple Books, VLC, most audiobook apps. If your device or program does not accept it, convert the file to a format it does.
How do I convert an M4B file?
Drop the file into the converter on this page, choose the target format — MP3, WAV, OGG, FLAC and M4A and others — and press Convert. It is free, there is no account and several files can be converted at once.
Is M4B lossy or lossless?
M4B is a lossy format: it makes files small by discarding detail that is hard to notice. Converting it to another format cannot bring that detail back.
What is M4B good for, and what are its limits?
Best for: audiobooks. Watch out: music players treat it as a book, not as a song.
Is the M4B converter free, and how big can the files be?
It is free, with no account, no watermark and no daily limit. Files can be up to 10 GB each.