Ton
Mass · Also called: long ton, imperial ton, short ton, tonne
That is
1.016 t
1 ton (long (imperial))
The other way round: 1 t is 0.9842 tons.
- Period: medieval to today in restricted use
- Region: the UK
- Goods: shipping, coal, iron
Values
| Value | That is | Period | Used for |
|---|---|---|---|
| long (imperial) | 1.016 t | medieval to today in restricted use | shipping, coal, iron · the UK |
| short | 907.2 kg | 19th century to today | the US |
| tonne | 1 t | 1795 to today | international |
What the unit was used for
The long ton of 2240 pounds is the unit British coal, iron, steel and shipping were reckoned in for centuries.
It is 20 long hundredweight, and its awkward size is simply what you get building upward from a stone of 14 pounds.
The American short ton of 2000 pounds is about a tenth lighter, and the metric tonne sits between the two, within 1.6 per cent of the long ton, which is one reason British heavy industry converted with so little pain.
In shipping, note that gross and net tonnage are volume measures descended from the wine tun and not weights at all, while deadweight tonnage is a weight.
In the system
1 long ton = 20 long hundredweight = 160 stone = 2240 pounds
A story you will often hear
The long ton of 2240 lb is usually said to come from the wine tun, on the ground that a full tun weighed about that much.
What the evidence shows: Plausible and repeated everywhere, but no authoritative source for the causal link could be found. The shared spelling history of tun and ton makes the story attractive without making it evidence.