The imperial system of units, imperial system or imperial units is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed through a series of Weights and Measures Acts and amendments.
United States customary units form a system of measurement units commonly used in the United States and most U.S. territories, since being standardized and adopted in 1832. The United States customary system developed from English units that were in use in the British Empire before the U.S. became an independent country. The United Kingdom's system of measures was overhauled in 1824 to create the imperial system, which was officially adopted in 1826, changing the definitions of some of its units. Consequently, while many U.S. units are essentially similar to their imperial counterparts, there are noticeable differences between the systems.
The foot is a unit of length in the British imperial and United States customary systems of measurement. The prime symbol, ′, is commonly used to represent the foot. In both customary and imperial units, one foot comprises 12 inches, and one yard comprises three feet. Since an international agreement in 1959, the foot is defined as equal to exactly 0.3048 meters.
The units of measurement in use in Denmark are currently part of the metric system. A variety of other historical weights and measures have been employed throughout the nation's history.
The Dutch units of measurement used today are those of the metric system. Before the 19th century, a wide variety of different weights and measures were used by the various Dutch towns and provinces. Despite the country's small size, there was a lack of uniformity. During the Dutch Golden Age, these weights and measures accompanied the Dutch to the farthest corners of their colonial empire, including South Africa, New Amsterdam and the Dutch East Indies. Units of weight included the pond, ons and last. There was also an apothecaries' system of weights. The mijl and roede were measurements of distance. Smaller distances were measured in units based on parts of the body – the el, the voet, the palm and the duim. Area was measured by the morgen, hont, roede and voet. Units of volume included the okshoofd, aam, anker, stoop, and mingel. At the start of the 19th century the Dutch adopted a unified metric system, but it was based on a modified version of the metric system, different from the system used today. In 1869, this was realigned with the international metric system. These old units of measurement have disappeared, but they remain a colourful legacy of the Netherlands' maritime and commercial importance and survive today in a number of Dutch sayings and expressions.
The obsolete Finnish units of measurement consist mostly of a variety of units traditionally used in Finland that are similar to those that were traditionally used in other countries and are still used in the United Kingdom and the United States.
The units of measurement of German-speaking countries consist of a variety of units, with varying local standard definitions. While many were made redundant with the introduction of the metric system, some of these units are still used in everyday speech and even in stores and on street markets as shorthand for similar amounts in the metric system. For example, some customers ask for one pound of something when they want 500 grams.
As in the case of the Danes, the Norwegians' earliest standards of measure can be derived from their ship burials. The 60-Norwegian-feet-long Kvalsund ship was built ca. 700 AD and differs from the Danish boats less than it does from the Oseberg, Gokstad and Tune ships which all date from ca. 800 AD. Thwarts are typically spaced about 3 Norwegian feet apart.
Traditional Swedish units of measurement were standardized by law in 1665, prior to which they only existed as a number of related but differing local variants. The system was slightly revised in 1735. In 1855, a decimal reform was instituted that defined a new Swedish inch as 1⁄10 Swedish foot. Up to the middle of the 19th century, there was a law allowing the imposition of the death penalty for falsifying weights or measures. After a decision by the parliament in 1875, Sweden adopted the metric system on 22 November 1878, with a ten-year transition period until 1 January 1889.
The earliest recorded systems of weights and measures originate in the 3rd or 4th millennium BC. Even the very earliest civilizations needed measurement for purposes of agriculture, construction and trade. Early standard units might only have applied to a single community or small region, with every area developing its own standards for lengths, areas, volumes and masses. Often such systems were closely tied to one field of use, so that volume measures used, for example, for dry grains were unrelated to those for liquids, with neither bearing any particular relationship to units of length used for measuring cloth or land. With development of manufacturing technologies, and the growing importance of trade between communities and ultimately across the Earth, standardized weights and measures became critical. Starting in the 18th century, modernized, simplified and uniform systems of weights and measures were developed, with the fundamental units defined by ever more precise methods in the science of metrology. The discovery and application of electricity was one factor motivating the development of standardized internationally applicable units.
The line was a small English unit of length, variously reckoned as 1⁄10, 1⁄12, 1⁄16, or 1⁄40 of an inch. It was not included among the units authorized as the British Imperial system in 1824.
Hong Kong has three main systems of units of measurement in current use:
A number of different units of measurement were used in Argentina as its national system was derived from Spanish Castillian. The metric system was legally optional since 1863 and has been compulsory since 1887.
A number of different units of measurement were used in Brazil to measure quantities including length, area, volume, and mass as those units were derived from Portugal and had significant local variances.
A number of different units of measurement were historically used in Cyprus to measure quantities like length, mass, area and capacity. Before the Metric system, the Imperial system was used. In between 1986-1988, metric system was adopted in Cyprus.
Traditional Greek units of measurement were standardized and used in modern Greece before and alongside the adoption of the metric system in 1836. Metric units were finally made legally compulsory in 1922.
A number of units of measurement were used in Iceland to measure length, mass, area, capacity, etc. Since 1907, the metric system has been compulsory in Iceland.
A number of units of measurement have been used in Cambodia to measure length, mass, volume, etc. The metric system has been compulsory there since 1914.
A number of units of measurement were used in Paraguay to measure quantities including length, mass, area, capacity, etc. Metric system had been optional since 1890, and adopted since 1899 in Paraguay.
Korean units of measurement, called cheokgwan-beop or cheokgeun-beop in Korean, is the traditional system of measurement used by the people of the Korean peninsula. It is largely based on the Chinese system, with influence from Japanese standards imposed following its annexation of the Korean Empire in 1910. Both North and South Korea currently employ the metric system. Since 2007, South Korea has criminalized the use of Korean units in commercial contexts, but informal use continues, especially of the pyeong as a measure of residential and commercial floorspace. North Korea continues to use the traditional units, although their standards are now derived from metric conversions.
