How to measure dim weight
Dim weight or dimensional weight is a standard formula used throughout the airfreight industry that considers density when determining airfreight charges. A dim weight formula is used to consider the amount of space a package will take on an aircraft in relation to the weight of the package.
Carriers use separate dimensional weight calculations for domestic and international shipments based on a standard density - weight per unit volume. A density of 1/194 pound per cubic inch (1/7 the density of water) is used on domestic packages. A density of 1/166 (1/6 the density of water) is used internationally.
To determine the dimensional weight of a package: A) Multiply the package's length by the width by the height (round each number to the nearest whole inch). The result is the cubic size of the package. If this number is 1,728 inches or less, use the actual weight in your rate calculations. B) If this number is more than 1,728 inches, divide the cubic size by 194 to determine the dimensional weight (in pounds). Increase fractions of a pound to the next full pound.
Irregular shaped containers cost more to ship because they must treated as if they were rectangular. You measure length, width, and height at the extreme points.