Reefer Container Calculator (Red Load Line)

Reefer containers carry cargo that must stay at a controlled temperature, such as frozen shrimp and fish, tropical fruit, meat and pharmaceuticals. In a typical reefer, cold air from the refrigeration unit is blown along the T-floor (a floor with T-shaped channels), rises through the cargo and returns to the unit at the top. That is why the usable capacity is smaller than the internal volume: cargo must not go above the red load line on the side walls and must not cover the end of the T-floor at the door, so the air keeps circulating.

This tool works out the net volume below the red line. By default the load height is the internal height minus 150 mm; you can change it to match the marking on the container you use. You can also keep a door gap, and when you enter a carton size the tool counts cartons in the upright position only, because reefer cartons are designed with vent holes and a fixed stacking direction.

A reefer is built to maintain temperature, not to cool down warm cargo. Cargo should be pre-cooled to the carriage temperature before loading, and the container should not be pre-cooled and then opened in humid air, since that causes condensation. The list of typical temperatures in the tool is for orientation only; the setpoint, ventilation and humidity always follow the shipper's written instructions.