by Guest » Fri Sep 19, 2008 1:06 am
You're not really converting it, by freight charges consider both weight and volume, and charge whichever results in the highest charge. You generally need to know both the weight and the volume.
For airfreight, the breakpoint is a density of 0.1667 kg/L (or t/m³). If they charge by volume and a 1 m³ shipment exceeds 167 kg, they will switch and charge by weight.
If they charge by weight, but a 167 kg shipment occupies more than 1 m³, they will switch and charge by volume.
For truck and sea shipments, I think the rate structure is less universal and you need to ask your shipper, but 333 kg/m³ is common for truck and 1000 kg/m³ for sea shipment break points.