What is M4A (MPEG-4 Audio, usually AAC)?
M4A is the MP4 container holding only audio, usually AAC, and the default format of iTunes and Apple Music.
Voice memos and many downloads arrive as M4A. If a device or website refuses them, converting to MP3 fixes that; converting to M4A instead is the better choice for Apple devices.
File extensions: .m4a, .m4bMIME types: audio/mp4, audio/x-m4a
Advantages
- Better quality than MP3 at the same size
- Full metadata and cover art
- Native on iPhone, iPad and Mac
Disadvantages
- Lossy (unless it holds ALAC)
- Some older players and car radios do not read it
- File extension confuses some upload forms
Typical uses
- iTunes and Apple Music libraries
- Voice memos on iPhone
- Audiobooks (as M4B)
Compatibility
Plays in all current browsers, on Apple devices, Android and Windows; a few older hardware players only accept MP3.
Convert M4A to another format
Convert to M4A from another format
Frequently asked questions
Are my files uploaded to a server?
No. The conversion runs entirely in your browser with local code. Your files never leave your device, and there is no upload.
Is there a file size limit?
There is no limit on our side, but your browser memory is. Images work for very large files; for videos, files above a few hundred megabytes can fail on devices with little memory.
Will the quality suffer?
That depends on the target format and settings. Use the quality option to balance size and detail; lossless targets keep everything the source contained.
Which browsers are supported?
Current versions of Chrome, Edge, Firefox and Safari. Fast hardware paths are used where available, with a compatible fallback otherwise.