Air cargo freight is a single multiply the kilograms of freight cargo of "kilogram" to determine the number, but "kg" number refers to the number of billable weight kg of cargo, billable weight is not necessarily equal to the number of ordinary people to understand number of kilograms of cargo scales, and sometimes, a kilograms are metric scale "quantity".

　　Billable weight according to the physical weight of the goods and the goods "dimensional weight" after comparing the two, optional plans collection. Physical weight is well understood, is the weight of the cargo on the scale, and what is the goods "dimensional weight"? Due to the limited aircraft cargo hold space, airlines in collecting freight charges, in order to balance the relationship between the volume of goods and cargo weights, and by the international air transport Association (IATA) unified determines the "dimensional weight" of standard formulas. Air freight cargo volume weight (kg) = volume of cargo (length (cm) x width (cm) x height (cm))/6,000, that is, the volume of 6,000 cubic centimeters is equivalent to 1 kg of goods return calculation, conversion, 1 cubic meter volume of goods to be calculated in accordance with 167 kg of freight.

　　In accordance with physical weight and volume weight optional large billing of principles, if goods of share small and units volume partial large, such as cotton, woven crafts,, so should measurement goods of volume, under above formula calculation out volume weight, and, will goods of actual weight and volume weight do comparison, optional its large who as billing weight, multiplied by single kg rates on came has should received freight.

　　This volume weight of billing way also also applies Yu aviation express company, each international express package in after express company of transit center Shi, are to by such as TNT Express Company of RPP (Revenue Protect Programme), system of detection, goods after optical scan, volume weight will is automatically entry express company of global information system, and and physical weight comparison Hou, is optional large billing.