Audio tool

Convert M4A Files to M4B on Your Device

Convert M4A to M4B in your browser for spoken-word publishing. The source remains on your device throughout local processing.

Route M4A → M4B

or drop here · up to 500 MB

Max 50 MB per file

Preview (optional)

When your browser supports it, your audio plays here. You can still convert your file if preview does not load.

Ready

Use upload name

The device processor performs decoding and encoding during the job during this M4A-to-M4B job.
High-resolution M4A footage increases conversion time and memory use.
Keep the source until the M4B result passes a full playback check.

M4B serves audiobooks and chapter-aware Apple playback, whereas M4A commonly serves Apple devices, podcasts, and compact music files.
For M4A-to-M4B delivery, plan for chapter metadata varying by player.
After leaving M4A, the receiving app must support the streams encoded inside M4B, not only its extension.

M4A to M4B taking too long? Process a shorter section to determine whether file size is the bottleneck.
M4B converted from M4A not opening? Test a compatible player and inspect the output streams.
If M4B is rejected, compare its codec and stream settings with the destination specification.

When does M4A to M4B conversion make sense?

It is useful when M4A media created for everyday audio delivery must enter a M4B system designed for spoken-word publishing.

Where is the M4A source processed?

The browser prepares M4B from M4A on this device instead of sending the source to a remote conversion server.

How can I approve M4B converted from M4A?

Test the M4B file in the receiving app and compare duration, channels and loudness with the M4A source.

Quick use cases