Free Online M4B Converter
An audiobook container with chapter marks that ordinary players ignore.
Up to 50 MB per file. Sign up free to convert files up to 100 MB.
| File name | Size | Convert to |
|---|
Pick a format to convert to.
Checking files and selected output formats.
How to convert M4B audiobooks online
Convert M4B audiobook files to MP3 or WAV to play on any device or app.
-
1
Upload your M4B audiobook
Drag and drop your M4B file, even long, multi-hour audiobooks. The full audio track is read for conversion (upgrade for files above the free size limit).
-
2
Choose MP3 or WAV
Pick MP3 for a small, universally-compatible file that plays on any phone, car stereo, or MP3 player, or WAV for uncompressed quality.
-
3
Download and listen anywhere
Download your audiobook and load it onto any device or app, no iTunes required. Uploads are deleted within 1 hour.
Audio Format Comparison
Choose the right output format when converting M4B audio files.
| Format | Quality | File size | Compatibility | Best For |
|---|---|---|---|---|
| MP3 | Lossy | Small | Universal | Music, podcasts, everyday playback |
| AAC | Lossy | Small | Apple, most devices | iPhone, iTunes, streaming |
| FLAC | Lossless | Large | Most players | Archiving, audiophile quality |
| WAV | Lossless | Very large | Universal | Audio editing, professional use |
| OGG | Lossy | Small | Web, Linux, games | Open-source apps, web audio |
| M4A | Lossy (AAC) | Small | Apple, most players | iTunes, Apple Music library |
Reasons to convert M4B audiobooks
M4B is Apple’s audiobook format and won’t open in many players. Convert to MP3 to listen on any phone, car stereo, smart speaker, or MP3 player.
M4B is tied to iTunes and Apple Books. Converting to MP3 or WAV frees your audiobooks to play in any app on Android, Windows, and beyond.
Many audiobook and podcast apps only accept MP3. Convert M4B so you can load books into your favourite listening app with bookmarking and speed control.
MP3 is easier to split and manage across devices than a single large M4B, making long audiobooks simpler to navigate and back up.
MP3 is the most durable, universally-supported audio format, ideal for long-term storage of an audiobook collection.
Convert M4B audio online, no desktop apps, no plugins. Files up to 100 MB are always free, and files are deleted from our servers within 1 hour.
About the M4B Format
M4B is an MP4 audio container with audiobooks in mind. The audio is normally AAC, exactly as in an M4A, but the extension signals that the file carries chapter markers and should remember your position, which is why audiobook players treat M4B differently from music files.
Chapters and bookmarking are the whole value, and they are also what gets lost in careless conversion: split an M4B into MP3s and the chapter structure usually disappears, leaving you to find your place manually in a file that may run for hours. Convert when you need playback on a device that will not accept M4B, and prefer formats that support chapter metadata where you can. Audiobooks bought from stores may carry DRM, which blocks conversion entirely.