Why volumetric weight exists
Carriers charge for the space your cargo takes up, not just its weight. A box of feathers weighs almost nothing but fills a lot of space. A box of bolts weighs a lot in a small space. Charging only by weight would mean the feather shippers pay almost nothing while taking 80% of the cargo hold.
The chargeable weight rule. Every airline, ocean carrier, and trucking company computes both your actual weight and your volumetric weight, and bills you on whichever is higher. The divisor differs by mode because the trade-off between space and weight is different on a plane vs a ship vs a truck.
Worked examples
Air freight, light cargo. 10 boxes of garments, each 60×40×40 cm, 5 kg each. Volumetric per box = (60×40×40) ÷ 5000 = 19.2 kg. Actual = 5 kg. Chargeable = 19.2 kg per box. Total chargeable = 192 kg even though actual is only 50 kg.
Air freight, heavy cargo. Same 10 boxes, but each 30 kg. Volumetric still 19.2 kg per box. Actual is now higher. Chargeable = 30 kg per box. Total = 300 kg.
Sea LCL. Volume in CBM × 1000 = weight-equivalent kg. So 5 CBM of cargo "equals" 5,000 kg. If actual weight is 3,000 kg, chargeable is 5 CBM (the volume figure dominates). If actual is 8,000 kg, chargeable is 8 CBM-equivalents (the weight dominates and you pay on weight).
Road freight. The ÷3000 divisor applies because trucks have looser space-to-weight ratios than planes. A 1m³ box would be charged as 333 kg by road vs 200 kg by air.
Notes for Kuwait shippers
International express couriers all use ÷5000. Domestic Kuwait courier rates may vary — confirm before booking.
Sea LCL into Shuwaikh. The 1 CBM = 1,000 kg rule is industry-standard, but minimum charges apply (typically 1 CBM minimum even if your shipment is smaller). Below 1 CBM, courier is usually cheaper.
Air freight from Yiwu/Shanghai/Mumbai. The ÷5000 rule is universal but the airline's actual divisor on your specific airwaybill governs. Some all-cargo carriers use ÷6000 for under-deck space.
Round up. Most carriers round chargeable weight to the next 0.5 kg (air) or whole kg (sea). The calculator above shows the exact figure — your invoice will round.
Now get the actual quote
The calculator gives you chargeable weight. The quote multiplies it by the carrier rate, adds origin handling, freight, customs and last-mile, and gives you one all-in number.
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