About MP3 and FLAC

MP3 is the most widely supported audio format there is — every browser, player, car stereo, and podcast app reads it. It's lossy, so quality is traded for file size, but at 192 kbps and up most listeners can't tell.

FLAC is lossless compression for audio — bit-identical to the source at roughly half the size of WAV. It's the archival format of choice for music collections and masters.

Converting MP3 to FLAC produces a lossless file, though detail already discarded by MP3's compression can't be recovered — the new file is a faithful copy of the MP3, not of the original recording.

How the conversion works

This tool runs FFmpeg — the same engine behind most media software — compiled to WebAssembly, entirely in your browser. Your file is read locally, converted locally, and saved straight from memory; nothing is ever uploaded, which also means no queues and no server-side file size limits.

The converter itself is a one-time ~31 MB download on your first conversion, cached by the browser afterwards. Once it's loaded, everything works offline.