Select your tray type (ladder, ventilated trough, solid bottom, or channel), enter the tray width and usable depth, then add cables by size and quantity. The calculator computes the total cable cross-sectional area and compares it against the applicable NEC fill limit. Calculate cable tray fill ratio, weight loading, and derating factors for multi-standard compliance. Save your cable tray sizing calculator results as branded PDF. Our free calculator helps you determine the correct tray size based on NEC and IEC standards. IEC 61537 covers cable tray and cable ladder systems for the support and accommodation of cables, while NEC Article 392 governs cable. Proper tray and ladder sizing ensures safe, efficient, and maintainable electrical installations in all engineering applications. 5 inches, in a 4-inch deep cable tray.