The dimensional weight is the calculation basis for carriage by air. The dimensional weight is related to the size of the packing used by the seller. The dimensional weight provides an easy way to calculate the actual air freight space required for the transportation of goods, which may be low in weight and bulky at the same time. The dimensional weight of the shipment is compared with the actual weight, whereas the higher value is used to determine the freight cost or rate.
This means as well, that a lightweight picture frame may turn out more expensive than a heavy television. Why? Because the picture frame is larger in size and volume than the small television.