M4A file format
MPEG-4 Audio
M4A is an audio-only MP4 file, usually holding AAC. It's the default for iTunes purchases, iPhone voice memos and many podcasts, with full tags and cover art.
| Property | M4A |
|---|---|
| File extensions | .m4a, .m4b |
| MIME type | audio/mp4 |
| Introduced | 2003 by Apple / MPEG |
| Compression | Lossy (AAC) or lossless (ALAC) |
| Typical bitrate | 128–256 kbps |
| 3-minute song | ≈ 3.6 MB at 160 kbps |
| Tags and cover art | Yes (full, with cover art) |
| Compatibility | Apple devices, Android, Windows 10+, browsers |
| Best for | iTunes/Apple Music libraries, voice memos, audiobooks |
What is an M4A file?
M4A is an MPEG-4 container that holds only audio — usually AAC, or Apple Lossless (ALAC). Apple popularised the extension with the iTunes Store in 2003; iPhone Voice Memos and many podcasts also use it. Audiobooks often use the related .m4b extension.
Strengths and weaknesses
M4A combines AAC's efficiency with proper metadata, cover art and accurate seeking. A few older car stereos, MP3 players and websites still only accept MP3.
When should you use M4A?
Use M4A for music libraries and voice recordings. Convert to MP3 for older devices; renaming M4A to M4R (with a 30-second cut) makes an iPhone ringtone.