Dimensional weight or chargable weight
Dimensional weight, also called DIM weight, is a pricing technique used for commercial freight transfer, including courier and postal services. Dimensional weight is computed by multiplying length times width times height. Since the amount of space on a delivery truck is limited, dimensional weight takes into account package density to determine shipping rates. So even if you have a lightweight package, it could be worth it to calculate DIM. Freight carriers like USPS, FedEx, or UPS calculate shipping charges based on whichever number is greater: the actual weight of the package or its calculated dimensional weight. Whichever is higher becomes your billable weight.