Click the "Select File" button above, and choose your M4B file.
You'll see a preview.
Click the "Convert file to..." button to save your file in the format you want.
Convert M4B to another file type
The converter easily converts your M4B file to various formats - free and online. No Media Player or extra software needed.
Convert a file to M4B
The converter also works in reverse, so you can convert other Audio formats to M4B with high quality output.
About M4B files
An M4B file is an MPEG-4 audio container designed specifically for audiobooks and podcasts. While technically nearly identical to the music-focused M4A format (both typically use AAC encoding), the M4B extension signals players to support "bookmarking" - allowing you to pause and resume playback from the exact same spot later. This format also supports chapter markers, letting listeners skip between sections of a book. However, this specialized behavior creates friction outside the Apple ecosystem. Many M4B files purchased from the iTunes Store or Apple Books are locked with FairPlay DRM, meaning they cannot be played on unauthorized devices, Android phones, or standard MP3 players. Even DRM-free M4B files often fail to play on car stereos or older media centers that don't recognize the extension. To fix this, users typically convert M4B to MP3 for universal compatibility (losing the chapter markers but gaining playback on any device) or simply rename the file to M4A if the file is DRM-free and they just need a compatible player to open it.
Use Convert.Guru to open and convert your M4B file.
If you want to convert M4B file to MP3, FLAC, WAV, AAC, OGG, WMA, M4A, AIFF, OPUS, ALAC, APE or WV, you can use Apple Books or similar software from the "Audiobook Storage" category. In the File menu, look for Save As… or Export….
To convert MIDI, AAC, TTA, AU, WV, DTS, MID, FLAC, RA, MP3, PCM or WAV files to M4B, try Apple Books or another comparable tool in the "Audiobook Storage" category.
The M4B Converter Story
The history of Convert.Guru began over 25 years ago in California with Tom Simondi’s file-format database. A former contributor to Space Shuttle development and a software pioneer of the 1980s, Simondi established a trusted resource for file type analysis that was even referenced by Microsoft Windows XP. Today, we use modern technology to process and convert thousands of file formats while continually improving our M4B converter.