Correlated Color Temperature (CCT) classifies white light by its perceived warmth or coolness, measured in Kelvin (K). 2700–3000K = Warm White (homes, restaurants, hospitality)—creates cozy atmosphere. 3500–4100K = Neutral White (offices, retail)—balanced, natural appearance. 5000–6500K = Cool White/Daylight (warehouses, hospitals, task lighting)—promotes alertness and visual acuity. CCT is independent of CRI; a 5000K source can have CRI70 or CRI90. Selection depends on application: cooler CCT for productivity, warmer for comfort.