The Cable Tray Sizing Calculator is an electrical calculator tool designed to determine the correct cable tray dimensions for electrical installations. Accurate fill ratio analysis and tray sizing per NEC, IEC 60364, and BS 7671 standards. Select Fill Standard: Choose 40% for power cables (NEC compliant) or 50% for. The right cable tray sizing calculator helps engineers turn cable schedules into a verified tray width and fill check before material ordering and site installation. Enter your cable schedule below to get started.