Ever wondered about tonne vs ton...and why a ton weighs differently in the US than in UK?
a tonne in US and UK is 2,204 pounds (known as a metric ton = 1000kg )
a ton in US is 2000 pounds (known as a short ton)
a ton in UK is 2240 pounds (known as a long ton).
"why the difference between US and UK/Commonwealth weights?" you ask:
well, 1kg =2.204 pounds, so the tonne's 2,204 pounds is easily derived and is the same in UK and US..
The short ton and long ton are both derived from being equal to 20 hundredweight (an old Imperial unit of weight). In US a hundredweight =100 pounds ...thus a US (i.e. short) ton is 20 x 100 = 2000pounds.
In UK a hundredweight is/was defined as being 8 stone. There's 14 pounds to a stone therefore 112 pounds in a hundredweight (i.e. 8 x 14).
20 hundredweight thus equals 20 x 112= 2240 pounds.