LUFS (Loudness Units relative to Full Scale) is the unit that finally measures how loud audio actually sounds, not just how high its peaks are. It comes from ITU-R BS.1770, which applies a K-weighting filter to mimic the ear and then gates out silence before averaging. One LUFS equals one decibel, and the scale is negative because it is referenced to full scale. Every platform publishes a target: roughly -14 LUFS for streaming music (Spotify, Apple Music, YouTube), -23 LUFS for European broadcast (EBU R128), and -24 LKFS for US broadcast. Hitting the target is what stops your content being turned up or down on playback.
