# Difference Between Ton and Metric Ton

## Main Difference – Ton vs. Metric Ton

Ton and the metric ton (the metric ton is also known as the tonne) are both units for measuring mass. The main difference between the ton and metric ton is that the ton has traditionally been a unit of mass in Imperial and US Customary systems of units, whereas metric ton is a unit of mass that has been defined using the international “SI” system of units (“Système International d’Unités“). Note, however, that the metric ton itself is not an official SI unit. Currently, the ton used in the United States is also defined using the SI system of units.

## What is a Ton

The values of the ton in Imperial and US Customary had been slightly different. Although both systems had used the same definition for the pound, the ton in the Imperial system was taken to have the mass of 2240 pounds, while the ton in the US Customary system was taken to have the mass of 2000 pounds. The Imperial ton is often called the long ton while the US ton is called the short ton.

In the USA, the pound was re-defined under the Mendenhall Order of 1893 such that the mass of 2.20462 pounds would exactly equal one kilogram. Following this definition, the mass of one (short) ton, according to the US Customary system of measurements, should have a mass of 907.18474 kilograms. The mass of the ton and metric ton are therefore intimately related.

## What is a Metric Ton (Tonne)

A metric ton is taken to be the mass of 1000 kilograms, or 1 megagram. The kilogram itself is defined under the SI system as the mass of the “international prototype of the kilogram”, which is a mass of a piece of metal kept in Sèvres, France in a vault in a basement of the Pavillon de Breteuil. Over the years, the mass of this piece of metal has increased slightly, meaning that mass of the metric ton (and consequently the ton, too) have increased by a very small amount.

Interestingly, mass is the only base SI unit which has not been given a definition that allows a specific mass to be reproduced in a laboratory. Recently, there has been a drive to redefine the kilogram to give it a fixed value. If one of these proposals are accepted, the metric ton, as well as the ton, would begin to have fixed values.

## Difference Between Ton and Metric Ton (Tonne)

The difference between ton and metric ton in terms of mass is 92.81526 kg, with the metric ton being heavier.

### Definition

Ton: Traditionally defined using the mass of the prototype of an “avoirdupois pound”. Now defined using the kilogram.

Metric ton: Defined using the kilogram.

### Value

Ton: Lighter, 1 (short) ton = 907.18474 kg.

Metric ton: Heavier, 1 metric ton= 1000 kg.