Convert & download
Convert AAX to M4B, chapters included
AAX and M4B are close relatives: both are AAC audio in an MP4-style container with chapters. Converting AAX to M4B gives you a single, open audiobook file that keeps chapter navigation and plays in almost any audiobook app.
Updated
How to do it
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1
Get AudiblePort
Install it on Windows, macOS or Linux and sign in to Audible.
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2
Queue your books
Select books from your library and download them.
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3
Choose M4B
Convert to M4B and get one chaptered file per book.
Why M4B is the natural target for AAX
Because both formats share the same building blocks, M4B is the most faithful way to take a book out of the Audible ecosystem: one file per book, chapter markers, cover art and resume position support in players that offer it.
- One file per book instead of dozens of fragments
- Chapter markers carried over from the original
- Recognized by Apple Books, Audiobookshelf, BookPlayer and more
Built for whole libraries
Converting a single book by hand is easy; converting four hundred is not. AudiblePort queues your entire library and converts books in parallel, with live progress and your output organized in one folder.
Frequently asked questions
Does the M4B keep the original chapters?
Yes. Chapter markers are written into the M4B so you can jump between them.
Does it work with AAXC too?
Yes. AudiblePort handles both AAX and AAXC books.
Can I rename the M4B file extension to .m4a?
M4B and M4A are the same container; the .m4b extension just tells players it's an audiobook. Keep .m4b for audiobook apps.