M4A Audio — MPEG-4 audio container, commonly AAC-encoded.
Quick facts
What is .m4a
A .m4a file is a M4A Audio — MPEG-4 audio container, commonly AAC-encoded.
In the mime-db registry it maps to audio/mp4, and it is marked as non-compressible. When serving .m4a over HTTP, set the Content-Type header as shown in Developer info below.
Related entities: it maps to audio/mp4 — and is delivered over HTTP via the Content-Type header.
How to open .m4a files
Developer info
When served over HTTP, responses should set the following header:
Content-Type: audio/mp4
Common software that reads/writes .m4a:
Relation chain
Related extensions
Related MIME types
Common uses
How to edit .m4a files
How to create .m4a files
Frequently asked questions
Common options include iTunes, VLC, QuickTime. You can also open many of these files with built-in viewers or a browser.
Create a new file in any text editor or the app that owns the format and save it with the .m4a extension.
audio/mp4 is the media type identifier used for .m4a files during network transfer (for example in the HTTP Content-Type header).
Sources & standards
Updated 2026-08-18
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