LKFS

Loudness units relative to full scale (LUFS), also known as 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. LUFS is a synonym for LKFS that was introduced in EBU R 128.

LKFS is standardized in ITU-R BS.1770. In March 2011, the International Telecommunication Union (ITU) introduced a loudness gate in the second revision of the recommendation, ITU-R BS.1770-2. In August 2012, the ITU released the third revision of this recommendation ITU-R BS.1770-3. In October 2015, the ITU released the fourth revision of this recommendation ITU-R BS.1770-4. In November 2023, the ITU released the fifth revision of this recommendation ITU-R BS.1770-5.