How to use the M4B converter
- Choose a file. Drop an M4B file to convert it to something else, or any other audio file to convert it to M4B.
- Check "Convert to". The converter picks MP3 for M4B files and M4B for everything else; change it if you need something different.
- Adjust quality if you want a smaller or higher-quality file.
- Click Convert and download the result.
What is an M4B file?
M4B is an M4A file marked as an audiobook. Apple Books and many audiobook apps remember your listening position in M4B files and can show chapters. Audiobooks bought from stores such as Audible are copy-protected and cannot be converted.
M4B is mainly used for audiobooks and long spoken-word recordings. It plays on Apple Books, iTunes, VLC and audiobook apps on Android.
M4B at a glance
| Full name | MPEG-4 Audiobook |
|---|---|
| Type | Audio |
| Created by | Apple, 2003 |
| Compression | Lossy |
| Codec | AAC |
| Can be created here | Yes |
Pros and cons of M4B
Good
- Remembers playback position
- Supports chapters
Not so good
- Not supported by many car stereos and MP3 players
Common M4B problems and fixes
An audiobook (M4B) will not play in the car
Convert M4B to MP3, then split it into parts if it is very long.
Popular M4B conversions
Frequently asked questions
How do I open an M4B file?
M4B files play on Apple Books, iTunes, VLC and audiobook apps on Android. If yours will not open, convert it to MP3 on this page; that format plays on any device.
How do I convert a file to M4B?
Drop any audio file on this page. "Convert to" is set to M4B automatically for files that are not M4B already.
Do I have to pay or sign up to use the M4B converter?
No. There is no account, no payment and no watermark. The only limit is 1 GB per file, set by what browsers can handle.
Are my files safe?
Yes. Files are converted locally in your browser and are never uploaded. When you close the page, nothing is left behind.
Is M4B lossy?
Yes, M4B normally uses lossy compression, which removes detail you are unlikely to notice to keep files small.