Audio File Formats Compared
The common audio file formats side by side — lossless vs lossy, rough file size, and what each is best used for. WAV, AIFF, FLAC, ALAC, MP3, AAC, Ogg Vorbis and Opus.
| Format | Ext | Compression | Size | Best for |
|---|---|---|---|---|
| WAVUncompressed PCM | .wav | Lossless | Very large | The studio interchange standard; universal. |
| AIFFUncompressed PCM (Apple) | .aiff | Lossless | Very large | Apple's WAV equivalent. |
| FLACFree Lossless Audio Codec | .flac | Lossless (compressed) | ~50–60% of WAV | Archiving and hi-fi distribution; open. |
| ALACApple Lossless | .m4a | Lossless (compressed) | ~50–60% of WAV | Lossless inside the Apple ecosystem. |
| MP3MPEG-1 Audio Layer III | .mp3 | Lossy | Small | Universal compatibility; legacy default. |
| AACAdvanced Audio Coding | .m4a | Lossy | Small (better than MP3) | Streaming, YouTube, Apple Music. |
| Ogg VorbisVorbis in an Ogg container | .ogg | Lossy (open) | Small | Open-source; common in games. |
| OpusIETF Opus | .opus | Lossy (open) | Smallest at low bitrate | Voice, streaming, WebRTC, Discord. |
"Lossless" keeps every bit of the original; "lossy" discards inaudible detail for much smaller files. Estimate uncompressed sizes with the audio file size calculator.
How to read this
Two things to keep separate: the container (the file wrapper) and the codec (how the audio is encoded). A .wav is usually uncompressed PCM but need not be.
uncompressed WAV, AIFF — PCM samples, largest
lossless FLAC, ALAC, WavPack — ~50–60% of PCM, identical audio
lossy MP3, AAC, Opus, Vorbis — smaller, discards dataNotes & gotchas
- Work uncompressed, deliver compressed. Every lossy encode discards information permanently, and re-encoding compounds it.
- Lossless really is lossless — FLAC decodes bit-identical to the PCM it came from. The only cost is CPU.
- Opus beats MP3 at low bitrates comfortably, and is the better choice for anything web-delivered today.
- 32-bit float is increasingly the recording default because clipping becomes recoverable in the box.
- WAV has a 4 GB limit from its 32-bit size field. Long multitrack recordings need RF64 or a different container.