A ton is any of various actual or nominal units of weight. The short ton commonly used in the US is 2,000 pounds, the long ton is 2,240 pounds. The metric ton or tonne (t) is 1,000 kilograms (2,204.62 pounds). The ton used for measuring ships' cargoes is 40 cubic feet in the US, 42 cubic feet in the UK. The register ton used for describing the capacity of merchant ships is 100 cubic feet; displacement ton used for describing warships (equivalent to 35 cubic feet of sea water) refers to the weight of water displaced by the ship – and hence to the actual weight of the ship.