Convert AAC to FLAC — Free Online Converter

AAC delivers perceptually transparent audio through lossy compression, typically at 128-256 kbps. FLAC (Free Lossless Audio Codec) stores audio with perfect bit-for-bit accuracy while achieving 50-70% compression versus raw PCM. Converting AAC to FLAC decodes the lossy AAC data and re-encodes it losslessly, producing a file that preserves every sample the AAC decoder outputs. This is commonly done for archival purposes or to prepare files for workflows that require lossless input.

Lossless audio editors and mastering chains expect FLAC or WAV input. If you apply effects to an AAC file and re-export as AAC, you compound lossy artifacts with each generation. Converting to FLAC first gives you a lossless working copy that survives unlimited editing cycles without further degradation. FLAC is also the standard archival format on Linux and Android, supported natively without extra software.