Carriers take both the size and weight of your package into consideration when determining the shipping cost. The weight of the ppackage is important, but sometimes the amount of space the package takes up on the truck or plane is given even more consideration! Dimensional, or volumetric, weight is a method of measurement calculated using the dimensions (length x width x height) of the package. Shipping cost is based on the greater of the actual weight or dimensional weight. The formula for calculating the dimensional weight of a package shipped internationally is: (Length x Width x Height [in inches]) / 139 = Dimensional Weight (in pounds).