he British ton is the long ton, which is 2240 pounds, and the U.S. ton is the short ton which is 2000 pounds.
Both tons are actually defined in the same way. 1 ton is equal to 20 hundredweight. It is just the definition of the hundredweight that differs between countries. In the U.S. there are 100 pounds in the hundredweight, and in Britain there are 112 pounds in the hundredweight. This causes the actual weight of the ton to differ between countries.
To distinguish between the two tons, the smaller U.S. ton is called short, while the larger British ton is called long.
There is also an third type of ton called the metric ton, equal to 1000 kilograms, or approximately 2204 pounds. The metric ton is officially called tonne. The SI standard calls it tonne, but the U.S. Government recommends calling it metric ton.