Convert Long Ton to Kilogram

The long ton originated in medieval England as a standardized measure for trade, particularly for goods like coal and other bulk materials. It was defined as 20 long hundredweight, with each long hundredweight being 112 pounds. This measure became part of the British Imperial System in 1824 and has been widely used in maritime and industrial contexts, especially in the UK, before the metric system was more broadly adopted.

The kilogram originated during the French Revolution in the late 18th century as part of the metric system's development. Initially, it was defined as the mass of one cubic decimeter of pure water at 4°C, chosen for its universal availability and consistency. In 1799, a physical standard called the Kilogram of the Archives, a platinum cylinder, was created to represent the unit. Later, in 1889, the International Prototype of the Kilogram (IPK), a more precise platinum-iridium cylinder, was adopted as the global standard, stored in France with copies distributed worldwide.

Over time, physical changes in the IPK led to inconsistencies, prompting scientists to redefine the kilogram. In 2019, it was redefined based on the Planck constant (h), a fundamental constant of nature, linking the kilogram to unchanging physical properties rather than a physical object. This modern definition ensures long-term precision and stability for the unit of mass.