Convert Hundredweight (US) to Kilogram

The hundredweight originated in medieval England as a unit of mass for measuring grain and other agricultural products. It was defined as 100 pounds. The term "hundredweight" comes from the Latin word "centum", meaning "hundred". The hundredweight was used in trade and agriculture for centuries and was adopted in the United States as part of the U.S. customary system.

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.