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mp3fy

Files never leave your device. Any size, any length.

M4B to MP3.
No size, no length limits.

Audiobooks as MP3 for players that don’t support M4B.

M4B to MP3, without limits

On your device

M4B audiobook files (MPEG-4) usually carry AAC audio and come from Audible exports, iTunes audiobooks. Audiobooks as MP3 for players that don’t support M4B.

How it works

  • Drop the M4B file on this page (or choose it). Folders and many files at once are fine.
  • The audio is decoded and encoded to MP3 right here in your browser — your file is never uploaded.
  • Live progress shows speed and time left; when it’s done, save the MP3 or download everything as a ZIP.

Frequently asked

Is my M4B file uploaded?

No. M4B files convert inside your browser; nothing leaves your device.

Is there a file size or duration limit?

No. mp3fy streams the file while converting, so a 20 GB recording or a 10‑hour lecture works the same as a short clip.

What bitrate should I pick?

192 kbps is the sweet spot for music and speech; 128 kbps for voice notes and podcasts; 320 kbps if you want the maximum. You can also keep stereo or down‑mix to mono.

Are my tags and cover art kept?

Yes — title, artist, album and embedded cover art are carried over into the MP3 when the source has them.

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