Volumetric weight, sometimes called "dim" or dimensional weight, is
used when the space a shipment takes on an aircraft may cost more than
the shipment's actual weight.
You should calculate dimensional weight on every shipment, and
compare that to its actual weight, and use the greater of the two to
determine your shipping cost. Volumetric weight for international
shipments is calculated using the formulae below. Volumetric weights for
domestic shipments may vary, so please contact your local customer services department
or country web site.
Length x Width x Height in centimetres / 5000 = Volumetric Weight in kilograms rounded up to the nearest 0.5kg
Length x Width x Height in inches / 138.4 = Volumetric Weight in pounds rounded up to the nearest pound