File Convert

Convert AU to M4B

Free online AU-to-M4B converter — upload a AU file and download a M4B. Fast, private, no signup.

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AU vs M4B

AU

Sun/NeXT AU — a simple, long-lived PCM audio container.

About AU ↗

M4B

MPEG-4 audiobook (AAC, with chapter support).

About M4B ↗

AU to M4B: frequently asked questions

How do I convert AU to M4B?

Drop your AU file into the converter above — we auto-detect the real format from its bytes, convert it, and give you a M4B to download. No software to install.

Is the AU to M4B converter free?

Yes. Convert AU to M4B for free right in your browser, with no account needed to get started.

Is it safe and private?

Your file is transferred over an encrypted connection and anonymous uploads are temporary. You can also view and strip metadata (location, device, author) before you download.

What's the difference between AU and M4B?

Sun/NeXT AU — a simple, long-lived PCM audio container. MPEG-4 audiobook (AAC, with chapter support).

Related conversions

Convert AU to: MP3 · WAV · FLAC · M4A · AAC · AC3 · AIFF · CAF · DTS · M4R

Convert to M4B from: AAC · AC3 · AIFF · AMR · APE · CAF · DFF · DSF · DTS · FLAC

Browse all supported formats →