MP3
Also known as: MPEG audio, .mp3, mp3 file, MPEG-1 Audio Layer III
MP3 is a lossy audio format that shrinks music files by discarding sound details most people cannot hear. It is the most universally compatible audio format, though newer codecs like AAC achieve similar quality in smaller files.
- Lossy: discards inaudible detail to save space
- The most universally compatible audio format
- AAC sounds better at the same file size
Lossy compression explained
MP3 is lossy: it permanently removes audio data the human ear is least likely to notice, then compresses the rest. The result is a file a fraction of the size of the original recording, at the cost of some fidelity you usually cannot detect.
Quality depends on bitrate — higher bitrates keep more detail and produce larger files. The format cannot be made lossless, so heavily compressed MP3s lose detail that cannot be recovered later.
MP3 vs AAC vs lossless
MP3’s strength is universal playback — almost every device and app supports it. AAC is a newer lossy codec that generally sounds better at the same file size, which is why Apple Music and iTunes downloads use it. Lossless formats like FLAC keep every detail but produce much larger files.
For most listeners, audio is a small slice of storage compared with photos and video. A large music library still adds up, but compressing or streaming it frees far less than clearing video does.