In air freight, shipping costs are based on chargeable weight, which is the higher of actual gross weight and volumetric weight. Volumetric weight formula (IATA): Length × Width × Height (cm) ÷ 6,000 = volumetric weight in kg. Example: a package of 120×80×100 cm weighing 150 kg has volumetric weight of 160 kg, so chargeable weight is 160 kg. For multi-piece shipments, sum all volumes and divide by 6,000. Some airlines use 1:5 ratio (÷ 5,000). Air tariffs are typically degressive with weight brackets. Sometimes declaring a higher weight can be cheaper due to lower per-kg rates in the next bracket (pivotal weight).