Convert MP3 to M4B

Drop a MP3 file below and download it as M4B in seconds. Free, no signup, no watermark — and your file is deleted automatically after 14 days.

1. Upload your MP3 file — drag & drop or tap to browse.
2. Pick M4B as the target format and choose a quality preset.
3. Press Convert and download your M4B file when it's ready.

Is this MP3 to M4B converter free?

Yes — converting MP3 to M4B is completely free, with no signup, no watermark and no daily limit beyond fair-use queuing.

Is it safe to upload my files?

Your file is only used to perform the conversion. It is never shared, there are no ads or trackers, and both the original and the result are deleted automatically after 14 days — or immediately if you delete them yourself.

Does it work on a phone?

Yes. The converter runs entirely in the browser page — nothing to install — and the site is built mobile-first, so converting MP3 to M4B works on Android and iPhone.