What Is Lossless Audio Compression?
Lossless compression reduces file size without losing any audio data. Decompress the file and you get back the exact original, bit for bit. FLAC, ALAC, and WavPack are lossless codecs. They are the ZIP files of the audio world.
How Lossless Compression Works
Lossless codecs find mathematical patterns and redundancies in audio data. Silence compresses extremely well. Repeated patterns compress well. Simple signals compress more than complex ones. The encoder writes a compact representation of the data. The decoder reconstructs the original perfectly. No psychoacoustic tricks, no data discarded. The output is identical to the input. Common techniques include linear prediction, Rice coding, and run-length encoding.
Common Lossless Formats
FLAC: Free Lossless Audio Codec. Open-source. The most popular lossless format. Supported on Android, iOS, macOS, Windows, and most browsers. ALAC: Apple Lossless Audio Codec. Apple's answer to FLAC. Open-source since 2011 but primarily used in Apple's ecosystem. Equivalent compression to FLAC. WavPack: Supports hybrid mode — a lossy file plus a correction file that together reconstruct the original. Niche but powerful. APE (Monkey's Audio): High compression ratio but slower encoding and decoding. Less compatible than FLAC.
Compression Ratios
Lossless codecs typically reduce file size by 30-60%. The exact ratio depends on the audio content. A CD-quality album that is 600 MB as WAV becomes 300-400 MB as FLAC. Simple music (solo piano, quiet acoustic) compresses more. Dense, loud music (heavy metal, EDM) compresses less. Silence compresses to nearly nothing. Noise barely compresses at all. The compression ratio is not a quality setting — it is purely a function of the audio content.
When to Use Lossless
Archival: Preserve recordings at full quality forever. Music production: Keep stems and masters in lossless format. Music library: Build a personal collection that never degrades. Audiophile listening: If you have good headphones and quiet environments, lossless makes a difference. Distribution to services: Spotify, Apple Music, and Tidal accept lossless uploads and handle compression themselves.
Lossless vs Uncompressed
WAV and AIFF are uncompressed — no compression at all. FLAC and ALAC are lossless compressed — smaller files, identical quality. There is no audio quality difference between WAV and FLAC. The only difference is file size and metadata support. FLAC actually has better metadata handling than WAV. For storage and archival, FLAC beats WAV in every way — same quality, smaller files, better tags, built-in integrity checking.