We present LOMS.cz (Luminescence, Optical and Magneto-optical Software), an open-source computational platform that addresses the long-standing challenge of standardizing Judd-Ofelt (JO) calculations in rare-earth spectroscopy. Despite JO theory’s six-decade history as the fundamental framework for understanding Scientific Reports (Nature Portfolio) (IF: 4.3, Q1-MULTIDISCIPLINARY SCIENCES) or check Article page