Dimensional (or DIM) weight is a pricing method used by freight and shipping companies, including courier and postal services. DIM weight takes into account both a shipment’s weight and dimensions when calculating shipping charges—charging whichever is higher: the shipment’s actual weight or dimensional weight as measured by how much room a given shipment takes up).
The formula used to calculate DIM weight in pounds is:
1) Calculate the volume of your shipment in square inches. Multiply length by width by height in inches. Round each measurement to the nearest whole inch. The resulting total is the cubic size of your package.
1) Divide this by 166 for domestic US shipment, and by 139 for Puerto Rico, and international shipments