FLAC
Also known as: Free Lossless Audio Codec, .flac, flac file, lossless audio
FLAC (Free Lossless Audio Codec) is a lossless audio format that compresses music with no loss of quality — the decoded file is bit-for-bit identical to the original. That fidelity comes at a cost: FLAC files are several times larger than MP3 or AAC.
- Lossless: identical to the original after decoding
- Several times larger than MP3 or AAC
- Apple Lossless (ALAC) is the equivalent format
Lossless vs lossy
FLAC is lossless: it shrinks a recording without discarding any audio data, so it can be restored exactly. MP3 and AAC are lossy — they permanently delete detail to reach much smaller sizes. FLAC keeps everything, which is why audiophiles and archivists prefer it.
The price is space. A FLAC album can take several times the room of the same album in AAC, because nothing was thrown away to compress it.
Support and storage trade-offs
FLAC plays natively on Android and on iOS via the Files app and many third-party players, though Apple’s own ecosystem favors Apple Lossless (ALAC), an equivalent format. Streaming services that offer lossless tiers use formats like these.
A large lossless library is one of the few audio collections that can genuinely pressure storage. If space is tight, keeping lossless files in the cloud and streaming or downloading on demand is the simplest fix.