M4B Converter for Mac

Convert audio files to M4B audiobooks with chapters. Accepts MP3, FLAC, WAV, M4A, AIFF, and AAC. No account needed, works offline.

Download on Mac App Store

What It Does

Audiobook Binder Pro takes your audio files and converts them into a single M4B audiobook. The M4B format wraps AAC audio with chapter markers and metadata, so audiobook players treat it as a proper book rather than a music file.

Drop in a folder of MP3s from a lecture series. Or a set of FLAC recordings from a podcast. Or WAV files you recorded yourself. The app re-encodes everything to 128 kbps AAC, writes chapter markers at each file boundary, and saves the result as one M4B.

You keep full control over chapter order and naming. Add a cover image, set the title and author, then export.

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Wide Format Support

Import MP3, M4A, M4B, WAV, FLAC, AIFF, and AAC. Mix formats in the same project without any pre-conversion steps.

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Chapter Markers

Every input file becomes a chapter. Rename them, reorder them, and they're embedded in the M4B on export.

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Metadata and Cover Art

Set title, author, and narrator. Drag in a cover image. The app auto-extracts metadata from source files when available.

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Apple Books Ready

Double-click the exported M4B to add it to Apple Books. Chapters appear in the table of contents. Playback position syncs via iCloud.

Formats You Can Convert

MP3 is the most common input. Works with any bitrate, mono or stereo.

M4A files are already AAC audio. The app re-encodes them with chapter markers added.

FLAC is lossless, so you get the cleanest possible source for the AAC conversion.

WAV and AIFF are uncompressed formats often produced by recording software. Both work as input.

AAC files without a container are also accepted.

M4B files can be imported too, useful when you want to recombine or reorder existing audiobooks.

FAQ

What is M4B?

M4B is an MPEG-4 container with AAC audio, chapter markers, and bookmarking support. Apple Books, Plex, Prologue, and Audiobookshelf all recognize it as an audiobook format.

Is there a file size or length limit?

No. Convert 10 minutes of audio or 40 hours. The app has no artificial restrictions on project size or duration.

What bitrate does the M4B use?

128 kbps AAC. This is more than sufficient for spoken word and keeps file sizes reasonable. A 10-hour audiobook comes out around 550 MB.

Can I convert FLAC to M4B?

Yes. Drop FLAC files in and the app converts them to 128 kbps AAC inside the M4B container. You can mix FLAC with MP3 or other formats in the same project.

Does the converter work offline?

Completely. No internet connection needed, no account to create. The conversion runs locally on your Mac.

Convert Your Audio to M4B

One-time purchase · No subscriptions · Works offline