Loudness, K-weighted, relative to full scale (LKFS) is a standard loudness measurement unit used for audio normalization in broadcast television systems and other video and music streaming services.
[4][5] In March 2011, the International Telecommunication Union (ITU) introduced a loudness gate in the second revision of the recommendation, ITU-R BS.1770-2.
[9] Loudness units relative to full scale (LUFS) is a synonym for LKFS that was introduced in EBU R 128.
[10] The EBU has suggested that the ITU should change the unit to LUFS, as LKFS does not comply with scientific naming conventions and is not in line with the standard set out in ISO 80000-8.
[11] LKFS and LUFS are identical in that they are both measured in absolute scale and both equal to one decibel (dB).