Freight containers are used for transporting bulk cargo by road, air or sea. Containers can be loaded with goods such as boxes, cases, pallets, sacks and other cargo. The container’s capacity is rated by its cubic measurement as well as the maximum weight of the cargo it can carry. The internal capacity of the container is measured in cubic feet. This is calculated by multiplying the internal size of the container--the inside length, height and width. To maximize the amount of cargo that can be shipped inside a container or to avoid a shortage of space, it is important to correctly calculate the freight to be loaded.
Calculate the cubic measurement of the cargo by multiplying the height, length and width of each item to be loaded. If measuring in feet, multiply the length, width and height of the item in feet to arrive at the total in cubic feet. If measuring in inches, multiply the length, width and height in inches, and divide the total by 1,728 to arrive at the figure in cubic feet.
Multiply the cubic foot total by the number of items of that size to go inside the container. Check the final cubic feet total of all cargo items against the cubic foot capacity of the container (see Resources).
Calculate the overall weight of the payload by multiplying the weight of each item to be loaded. Be sure not to exceed the maximum weight rating of the container (see Resources).
The size of intercontinental containers used come in standard lengths of 10 feet, 20 feet, 30 feet and 40 feet.
The most popular containers used for sea freight are 20-foot and 40-foot containers.
The rating of the container is its maximum gross weight. That means the maximum weight allowed for the container, including its contents.
The tare mass (tare weight) is the weight of an empty container.
The payload is the weight of the cargo. Therefore, payload + tare mass = rating.
If the cargo is being loaded on pallets inside the container, remember to include the size, weight and quantity of the pallets in the overall calculation.
To make the job of calculating a container load easier, free and paid container load calculating software is available online.
Anneline Kinnear has been a writer since 1984. She specializes in article writing, short fiction and plays. Kinnear's work has appeared in “Personality” magazine, “BusinessWorld” magazine and “Business Unlimited.” Kinnear was Editor-in-Chief of “Business Unlimited” for three years. Kinnear owns a children's educational software publishing company, and is passionate about designing and developing children's educational software.