CBM stands for cubic meter, the standard size that international sea shippers use to calculate how much to charge for cargo that is less than a container load, or LCL. A CBM is defined as 1 meter high, wide and deep. You calculate it by multiplying the three dimensions of a box, crate or pallet in metric units. For example, a box that is 0.6 m high by 0.4 m wide by 1 m deep is 0.24 CBM. A CBM is approximately 35 cubic feet.
Weight vs. Volume
Shippers charge by volume for LCL freight. If your shipment takes up less volume than a full container load, you don't have to worry about its weight, up to a certain maximum. Very dense LCL freight, where density is weight divided by volume, is subject to weight pricing. The standard U.S. rule is to charge by weight if a box's density exceeds 45 pounds per cubic foot. Internationally, ocean freight shippers may set 1 CBM equal to a fixed number of kilograms, ranging from 500 to 1,000 depending on the shipper. Sea shippers may charge a minimum price that's equal to the charge for a 1 CBM box.