MP3

The most common audio file format, mp3 files lose some audio quality but keep the file sizes smaller, so you can fit more songs on a device.

WAV

Preserves original sound quality because the files aren’t compressed like mp3 and aac files are.

AAC, AAC+, eAAC+

Used for smaller file sizes than mp3, but with the same audio quality. AAC+ and eAAC+ are variations that optimize sound for even smaller file sizes.

M4A

A version of MP4, which are compressed files that can contain sound, video, and text.

WMA

About the same file size and audio quality as mp3. Owned and developed by Microsoft.

Real

Slightly smaller sound files and similar audio quality to mp3. Owned and developed by RealNetworks.