British Imperial System

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Regulating weights and measures under Henry VII

British Imperial System

measurement system

Also known as: Customary System, Imperial System, U.S. Customary System(Show More)

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June 23, 2026

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Regulating weights and measures under Henry VII — Regulating weights and measures under Henry VII Weights and measures being tested during the reign of Henry VII.

The British Imperial System is a measurement system that was officially used in Great Britain from 1824 until the adoption of the metric system began in 1965. This system evolved from various medieval units of measurement, including Roman, Celtic, and Anglo-Saxon systems.1

Key characteristics of the British Imperial System include:
* Units: It uses units such as pounds for weight, yards for length, and gallons for capacity.21
* Conversions: Unlike the metric system, which is based on powers of 10, the Imperial system has less neat conversions. For example, a mile is 5,280 feet, and a pound is 16 ounces.3
* Relationship to U.S. Customary System: The United States Customary System is derived from the British Imperial System, though there are some differences, such as the definition of a ton and the size of a gallon.1

The British Imperial System has been largely replaced by the metric system, which is now legally defined in metric terms.1

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Today in History—April 5
The U.S. Joins the Metric System—Sort Of
Those standards defined the U.S. Customary System—the measurements Americans know and love (inches, yards, pounds, and feet)—in relation to the metric system. The order determined that the fundamental standard of length was to be the meter, and the fundamental standard of mass was to be the kilogram. And the…
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Those standards defined the U.S. Customary System—the measurements Americans know and love (inches, yards, pounds, and feet)—in relation to the metric system. The order determined that the fundamental standard of length was to be the meter, and the fundamental standard of mass was to be the kilogram. And the…
Read More

measurement system
The English system
…the 19th century that a major overhaul occurred.
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…the 19th century that a major overhaul occurred.
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Imperial units
…units of measurement of the British Imperial System, the traditional system of weights and measures used officially in Great Britain from 1824 until the adoption of the metric system beginning in 1965. The United States Customary System of weights and measures is derived from the British Imperial System. Imperial units…
Read More
…units of measurement of the British Imperial System, the traditional system of weights and measures used officially in Great Britain from 1824 until the adoption of the metric system beginning in 1965. The United States Customary System of weights and measures is derived from the British Imperial System. Imperial units…
Read More

mechanics
Units and dimensions
…such as those of the British engineering system, are still in use in some places, but these are now defined in terms of the SI units.
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…such as those of the British engineering system, are still in use in some places, but these are now defined in terms of the SI units.
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metric versus Imperial converter
…United States, often called the Imperial System or the Customary System, does not have such neat conversions. One mile is 5,280 feet, four quarts make a gallon, and one pound is 16 ounces. Using the interactive tool below, one can easily convert quantities between the two systems.
Read More
…United States, often called the Imperial System or the Customary System, does not have such neat conversions. One mile is 5,280 feet, four quarts make a gallon, and one pound is 16 ounces. Using the interactive tool below, one can easily convert quantities between the two systems.
Read More

pint
…unit of capacity in the British Imperial and U.S. Customary systems of measurement. In the British system the units for dry measure and liquid measure are identical; the single British pint is equal to 34.68 cubic inches (568.26 cubic cm) or one-eighth gallon. In the United States the unit for…
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…unit of capacity in the British Imperial and U.S. Customary systems of measurement. In the British system the units for dry measure and liquid measure are identical; the single British pint is equal to 34.68 cubic inches (568.26 cubic cm) or one-eighth gallon. In the United States the unit for…
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quart
…unit of capacity in the British Imperial and U.S. Customary systems of measurement. For both liquid and dry measure, the British system uses one standard quart, which is equal to two imperial pints, or one-fourth imperial gallon (69.36 cubic inches, or 1,136.52 cubic cm). The U.S. system has two units…
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…unit of capacity in the British Imperial and U.S. Customary systems of measurement. For both liquid and dry measure, the British system uses one standard quart, which is equal to two imperial pints, or one-fourth imperial gallon (69.36 cubic inches, or 1,136.52 cubic cm). The U.S. system has two units…
Read More