A stowage factor is the volume required to stow a given weight of cargo on board a ship. Stowage factors are always estimates. Even if the volume and weight of cargo is calculated precisely, there are variations such as the shape of the storage compartment and the efficiency with which the shipper loads the cargo. The type of cargo shipped can also lead to variations in a stowage factor. For instance, compressed bales of agricultural products take up less room than uncompressed bales.
The formula for calculating a stowage factor is one long ton, or 2,240 pounds, multiplied by the volume in cubic feet. The result is divided by the cargo weight in pounds to find the stowage factor, which is the number of cubic feet required for stowing one long ton of a specific cargo. If you are using a metric measure, the formula is 1,000 kilograms times the volume in cubic meters divided by the cargo weight in kilograms. Suppose you have a cargo with a volume of 15 cubic feet and a weight of 900 pounds. The stowage computation is 2,240 pounds times 15 divided by 900. The stowage factor works out to 37.3 cubic feet per long ton.
