How to Convert Audiobooks (M4B, AAX) for Android and PC - Free & Offline

The digital audiobook industry has exploded in popularity, but the file formats used to deliver audiobooks are notoriously anti-consumer.

If you purchase or download a DRM-free audiobook, it frequently arrives as an M4B file.

The M4B format was created by Apple. It is nearly identical to an M4A audio file (using AAC compression), but it includes a special flag that tells iTunes and Apple Books to treat it as an audiobook. This allows for useful features like chapter markers and bookmarking your listening position.

However, if you do not use an iPhone or a Mac, the .m4b extension is a massive headache. Android smart phones, car stereos, generic MP3 players, and standard Windows media players frequently refuse to recognize or play the file.

The easiest way to unlock your audiobook so you can listen to it anywhere is to convert the M4B into a universal MP3.

Don’t Upload Your 15-Hour Audiobooks

Most people attempt to solve this by Googling an online audio converter.

Here is why that is a terrible idea for audiobooks: The average 15-hour audiobook is a massive file, often exceeding 500MB or even 1GB in high quality.

1. File Size Limits: Almost every free online converter has a strict 100MB file limit. Your audiobook will instantly be rejected unless you buy a premium subscription.
2. Wasted Data: If you are trying to convert an audiobook while traveling, uploading a 500MB file to a cloud server and downloading a 300MB MP3 will destroy your mobile data limit and take hours.

Convert Audiobooks Instantly on Your Device

We engineered the GetAnyFile Audio Converter to eliminate file size limits by doing the processing locally.

Because our tool uses WebAssembly to run an audio engine natively inside your web browser (like Chrome or Safari), your massive M4B file never leaves your computer or phone.

Why Local Conversion is Superior:

• Zero Limits: We don’t care if your audiobook is 50 hours long and 2GB. Since we don’t host the file, we don’t put limits on your usage.
• Instant Processing: You skip the upload entirely. Your PC’s local processor does the heavy lifting, transcoding the audio directly into your downloads folder.
• 100% Privacy: Your downloaded media isn’t logged or copied to an insecure cloud database.

How to Unlock Your Audiobook

Converting your M4B file takes just a few clicks:

1. Launch our M4B to MP3 Converter.
2. Drop your audiobook file into the dropzone (or tap to select it if you’re on Android).
3. Ensure the output format is set to MP3.
4. (Optional) If you want to save space, you can lower the audio bitrate to ~64kbps, which is standard for spoken voice.
5. Click Convert.

Watch the status bar fill. Because no internet upload is required, the conversion begins instantly, leveraging your device’s hardware.

Free your audiobooks from restrictive, proprietary formats. Listen to your stories on the hardware you prefer.