How do FLAC and AACcompare? Here's everything you need to know to choose the right format — and how to convert between them.
Free Lossless Audio Codec
FLAC is the leading open-source lossless audio format. It compresses audio files to about 50-60% of their original size without any quality loss — perfect for audiophiles and music archival.
Advanced Audio Coding
AAC is the successor to MP3, offering better sound quality at lower bitrates. It's the default audio format for Apple Music, YouTube, and most streaming platforms.
| Specification | FLAC | AAC |
|---|---|---|
| Full name | Free Lossless Audio Codec | Advanced Audio Coding |
| Extension | .flac | .aac |
| MIME type | audio/flac | audio/aac |
| Category | Audio | Audio |
| Developer | Xiph.Org Foundation | ISO / Fraunhofer / Dolby / Sony / Nokia |
| Year introduced | 2001 | 1997 |
| Compression | Lossless | Lossy |
FLAC preserves full audio quality with no compression artifacts. AAC offers much smaller files at the cost of some quality. For casual listening, AAC is fine. For production or archival, use FLAC.
Need to switch formats? Convert for free with SquishConvert.