ton

Ton is a unit of mass used in several measurement systems. The most common form worldwide is the metric ton, or tonne, defined as exactly 1,000 kilograms. The symbol t is standard for the tonne. While widely used in commerce and industry, the tonne is not an SI base unit, but it is accepted for use with the SI as a non-SI unit expressed in kilograms.

Three major variants are encountered: the metric ton (tonne) at 1,000 kg; the short ton used in the United States at 2,000 pounds (about 907.18474 kg); and the long ton used in the United Kingdom at 2,240 pounds (about 1,016.0469 kg). Consequently, 1 tonne is approximately 1.10231 short tons and 0.98421 long tons.

Ton measurements are common in shipping, construction, mining, and vehicle specifications, especially when describing mass, capacity, or cargo. In shipping, ships’ tonnage historically referred to volume or size; today gross tonnage and deadweight tonnage denote overall size and carrying capacity rather than a precise mass. In scientific contexts, mass is usually given in kilograms, with “ton” used primarily in everyday language and commerce to avoid longer figures.