The calculator computes the cross-sectional area of all cables and compares it to the available tray cross-section. Calculate the appropriate cable tray size based on your cables and fill requirements. From an engineering standpoint, cable tray dimensions are not. Calculate cable tray fill ratio, weight loading, and derating factors for multi-standard compliance. Select your tray type (ladder, ventilated trough, solid bottom, or channel), enter the tray width.