The foot (
feet), standard symbol: ft,
is a
unit
Unit may refer to:
Arts and entertainment
* UNIT, a fictional military organization in the science fiction television series ''Doctor Who''
* Unit of action, a discrete piece of action (or beat) in a theatrical presentation
Music
* ''Unit'' (alb ...
of
length
Length is a measure of distance. In the International System of Quantities, length is a quantity with dimension distance. In most systems of measurement a base unit for length is chosen, from which all other units are derived. In the Interna ...
in the
British imperial
The British Empire was composed of the dominions, colonies, protectorates, mandates, and other territories ruled or administered by the United Kingdom and its predecessor states. It began with the overseas possessions and trading posts esta ...
and
United States customary systems of
measurement
Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events.
In other words, measurement is a process of determining how large or small a physical quantity is as compared ...
. The
prime symbol
The prime symbol , double prime symbol , triple prime symbol , and quadruple prime symbol are used to designate units and for other purposes in mathematics, science, linguistics and music.
Although the characters differ little in appearance fr ...
, , is a customarily used alternative symbol.
Since the
International Yard and Pound Agreement of 1959, one foot is defined as 0.3048
meters
The metre (British spelling) or meter (American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its prefi ...
exactly. In both customary and imperial units, one foot comprises 12
inch
Measuring tape with inches
The inch (symbol: in or ″) is a unit of length in the British imperial and the United States customary systems of measurement. It is equal to yard or of a foot. Derived from the Roman uncia ("twelfth") ...
es and one
yard
The yard (symbol: yd) is an English unit of length in both the British imperial and US customary systems of measurement equalling 3 feet or 36 inches. Since 1959 it has been by international agreement standardized as exactly 0.914 ...
comprises three feet.
Historically the "foot" was a part of many local systems of units, including the
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
,
Roman
Roman or Romans most often refers to:
*Rome, the capital city of Italy
*Ancient Rome, Roman civilization from 8th century BC to 5th century AD
*Roman people, the people of ancient Rome
*''Epistle to the Romans'', shortened to ''Romans'', a letter ...
,
Chinese
Chinese can refer to:
* Something related to China
* Chinese people, people of Chinese nationality, citizenship, and/or ethnicity
**''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation
** List of ethnic groups in China, people of ...
,
French, and
English
English usually refers to:
* English language
* English people
English may also refer to:
Peoples, culture, and language
* ''English'', an adjective for something of, from, or related to England
** English national ide ...
systems. It varied in length from country to country, from city to city, and sometimes from trade to trade. Its length was usually between 250 mm and 335 mm and was generally, but not always, subdivided into 12 inches or 16
digits.
The United States is the only industrialized nation that uses the
international foot
The foot ( feet), standard symbol: ft, is a unit of length in the British imperial and United States customary systems of measurement. The prime symbol, , is a customarily used alternative symbol. Since the International Yard and Po ...
and the
survey foot
The foot ( feet), standard symbol: ft, is a unit of length in the British imperial and United States customary systems of measurement. The prime symbol, , is a customarily used alternative symbol. Since the International Yard and Po ...
(a
customary unit of length) in preference to the meter in its commercial, engineering, and standards activities.
The foot is legally recognized in the United Kingdom; road signs ''must'' use imperial units (however, distances on road signs are always marked in miles or yards, not feet), while its usage is widespread among the British public as a measurement of height. The foot is recognized as an alternative expression of length in Canada officially defined as a unit derived from the meter although both the U.K. and Canada have partially
metricated their units of measurement. The measurement of
altitude
Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context ...
in international
aviation
Aviation includes the activities surrounding mechanical flight and the aircraft industry. ''Aircraft'' includes fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air craft such as hot air ...
is one of the few areas where the foot is used outside the English-speaking world.
The length of the international foot corresponds to a human foot with
shoe size
A shoe size is an indication of the fitting size of a shoe for a person.
There are a number of different shoe-size systems used worldwide. While all shoe sizes use a number to indicate the length of the shoe, they differ in exactly what they me ...
of 13 (UK), 14 (US male), 15.5 (US female) or 48 (EU sizing).
Historical origin
![Determination of the rute and the feet in Frankfurt](https://upload.wikimedia.org/wikipedia/commons/0/0c/Determination_of_the_rute_and_the_feet_in_Frankfurt.png)
Historically, the human body has been used to provide the basis for units of length.
The foot of an adult Caucasian male is typically about 15.3% of his height, giving a person of a foot-length of about , on average.
Archaeologists believe that, in the past, the people of
Egypt
Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...
,
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
, and
Mesopotamia
Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the F ...
preferred the
cubit
The cubit is an ancient unit of length based on the distance from the elbow to the tip of the middle finger. It was primarily associated with the Sumerians, Egyptians, and Israelites. The term ''cubit'' is found in the Bible regarding No ...
, while the people of
Rome
, established_title = Founded
, established_date = 753 BC
, founder = King Romulus (legendary)
, image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg
, map_caption ...
,
Greece
Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders with ...
, and
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
preferred the foot. Under the Harappan linear measures, Indus cities during the Bronze Age used a foot of 333.5 mm (13.2 in) and a cubit of 528.3 mm (20.8 in). The
Egyptian
Egyptian describes something of, from, or related to Egypt.
Egyptian or Egyptians may refer to:
Nations and ethnic groups
* Egyptians, a national group in North Africa
** Egyptian culture, a complex and stable culture with thousands of years of ...
equivalent of the foot—a measure of four palms or 16 digits—was known as the and has been reconstructed as about .
The Greek foot (, ) had a length of of a
stadion, one stadion being about ; therefore a foot was, at the time, about . Its exact size varied from city to city and could range between and , but lengths used for temple construction appear to have been about to ; the former was close to the size of the Roman foot.
The standard
Roman foot
Roman or Romans most often refers to:
*Rome, the capital city of Italy
*Ancient Rome, Roman civilization from 8th century BC to 5th century AD
*Roman people, the people of ancient Rome
*''Epistle to the Romans'', shortened to ''Romans'', a letter ...
() was normally about (97% of today's measurement),
[Hosch, William L. (ed.) (2010]
''The Britannica Guide to Numbers and Measurement''
New York, NY: Britannica Educational Publications, 1st edition. , p.206 but, in the provinces, the so-called (foot of
Nero Claudius Drusus
Nero Claudius Drusus Germanicus (38–9 BC), also called Drusus the Elder, was a Roman politician and military commander. He was a patrician Claudian on his birth father's side but his maternal grandmother was from a plebeian family. He was the ...
) was used, with a length of about . (In reality, this foot predated Drusus.)
Originally both the Greeks and the Romans subdivided the foot into 16
digits, but in later years, the Romans also subdivided the foot into 12 (from which both the English words "inch" and "
ounce
The ounce () is any of several different units of mass, weight or volume and is derived almost unchanged from the , an Ancient Roman units of measurement, Ancient Roman unit of measurement.
The #International avoirdupois ounce, avoirdupois ounce ...
" are derived).
After the fall of the Roman Empire, some Roman traditions were continued but others fell into disuse. In AD 790
Charlemagne
Charlemagne ( , ) or Charles the Great ( la, Carolus Magnus; german: Karl der Große; 2 April 747 – 28 January 814), a member of the Carolingian dynasty, was King of the Franks from 768, King of the Lombards from 774, and the first Holy ...
attempted to reform the units of measure in his domains. His units of length were based on the and in particular the , the distance between the fingertips of the outstretched arms of a man. The has 6 (feet) each of .
He was unsuccessful in introducing a standard unit of length throughout his realm: an analysis of the measurements of
Charlieu Abbey
Charlieu Abbey or St. Fortunatus' Abbey, Charlieu (french: Abbaye de Charlieu) was a Order of St. Benedict, Benedictine abbey located at Charlieu, Loire (département), Loire, Bourgogne, Burgundy, France. It was later a Cluniac priory.
History
Th ...
shows that during the 9th century the Roman foot of was used; when it was rebuilt in the 10th century, a foot of about
[The original reference was given in a round number of centimeters] was used. At the same time, monastic buildings used the Carolingian foot of .
The procedure for verification of the foot as described in the 16th century posthumously published work by
Jacob Köbel
Jacob Köbel (1462–1533) was a printer and publisher in Oppenheim.
Köbel graduated in arts and law from Heidelberg University in 1491. He appears to have then studied mathematics at Cracow, and is said to have been a fellow student of Coperni ...
in his book is:
England
![Imperial measurement standards, Greenwich](https://upload.wikimedia.org/wikipedia/commons/6/69/Imperial_measurement_standards%2C_Greenwich.JPG)
The
Neolithic
The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts ...
long foot, first proposed by archeologists
Mike Parker Pearson
Michael Parker Pearson, (born 26 June 1957) is an English archaeologist specialising in the study of the Neolithic British Isles, Madagascar and the archaeology of death and burial. A professor at the UCL Institute of Archaeology, he previous ...
and Andrew Chamberlain, is based upon calculations from surveys of
Phase 1 elements at Stonehenge. They found that the underlying diameters of the stone circles had been consistently laid out using multiples of a base unit amounting to 30 long feet, which they calculated to be 1.056 of a modern
international foot
The foot ( feet), standard symbol: ft, is a unit of length in the British imperial and United States customary systems of measurement. The prime symbol, , is a customarily used alternative symbol. Since the International Yard and Po ...
(thus 12.672 inches or 0.3219 m). Furthermore, this unit is identifiable in the dimensions of some stone
lintels
A lintel or lintol is a type of beam (a horizontal structural element) that spans openings such as portals, doors, windows and fireplaces. It can be a decorative architectural element, or a combined ornamented structural item. In the case of ...
at the site and in the diameter of the "southern circle" at nearby
Durrington Walls
Durrington Walls is the site of a large Neolithic settlement and later henge enclosure located in the Stonehenge World Heritage Site in England. It lies north-east of Stonehenge in the parish of Durrington, just north of Amesbury in Wiltshir ...
. Evidence that this unit was in widespread use across southern Britain is available from the
Folkton Drums
The Folkton Drums are a very rare set of three decorated chalk objects in the shape of drums or solid cylinders dating from the Neolithic period. Found in a child's grave near the village of Folkton in northern England, they are now on loan to ...
from
Yorkshire
Yorkshire ( ; abbreviated Yorks), formally known as the County of York, is a Historic counties of England, historic county in northern England and by far the largest in the United Kingdom. Because of its large area in comparison with other Eng ...
(
neolithic
The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts ...
artifacts, made from chalk, with circumferences that exactly divide as
integers
An integer is the number zero (), a positive natural number (, , , etc.) or a negative integer with a minus sign (−1, −2, −3, etc.). The negative numbers are the additive inverses of the corresponding positive numbers. In the language o ...
into ten long feet) and a similar object, the
Lavant drum
The Lavant drum is small cylindrical Neolithic chalk object excavated in 1993. It is similar to the Folkton drums, discovered over a century earlier and the Burton Agnes drum. Unlike the Folkton drums, the Lavant drum is undecorated; however, it ...
, excavated at
Lavant, Sussex, again with a circumference divisible as a whole number into ten long feet.
The measures of
Iron Age Britain
The British Iron Age is a conventional name used in the archaeology of Great Britain, referring to the prehistoric and protohistoric phases of the Iron Age culture of the main island and the smaller islands, typically excluding prehistoric Ir ...
are uncertain and proposed reconstructions such as the
Megalithic Yard are controversial. Later
Welsh legend
Welsh mythology (Welsh: ''Mytholeg Cymru'') consists of both folk traditions developed in Wales, and traditions developed by the Celtic Britons elsewhere before the end of the first millennium. As in most of the predominantly oral societies Celti ...
credited
Dyfnwal Moelmud
Dyfnwal Moelmud (Welsh for "Dyfnwal the Bald and Silent"; la, Dunvallo Molmutius; ) was accounted as an early king and lawmaker among the Welsh, credited with the codification of their standard units of measure. He also figures as a legendary ki ...
with the establishment of
their units, including a foot of 9 inches. The Belgic or North German foot of was introduced to England either by the
Belgic Celts during their invasions prior to the Romans or by the
Anglo-Saxons
The Anglo-Saxons were a Cultural identity, cultural group who inhabited England in the Early Middle Ages. They traced their origins to settlers who came to Britain from mainland Europe in the 5th century. However, the ethnogenesis of the Anglo- ...
in the 5th and 6th century.
Roman units
The ancient Roman units of measurement were primarily founded on the Hellenic system, which in turn was influenced by the Egyptian system and the Mesopotamian system. The Roman units were comparatively consistent and well documented.
Length
T ...
were introduced following
their invasion in AD 43. Following the
Roman withdrawal and
Saxon invasions, the Roman foot continued to be used in the construction crafts while the Belgic foot was used for land measurement. Both the Welsh and Belgic feet seem to have been based on multiples of the
barleycorn, but by as early as 950 the English kings seem to have (ineffectually) ordered measures to be based upon an iron yardstick at
Winchester
Winchester is a City status in the United Kingdom, cathedral city in Hampshire, England. The city lies at the heart of the wider City of Winchester, a local government Districts of England, district, at the western end of the South Downs Nation ...
and then
London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
.
Henry I Henry I may refer to:
876–1366
* Henry I the Fowler, King of Germany (876–936)
* Henry I, Duke of Bavaria (died 955)
* Henry I of Austria, Margrave of Austria (died 1018)
* Henry I of France (1008–1060)
* Henry I the Long, Margrave of the No ...
was said to have ordered a new standard to be based upon the length of his own arm and, by the Act concerning the
Composition of Yards and Perches
The Composition of Yards and Perches ( la, Compositio Ulnarum et Perticarum) or the Statute of Ells and Perches was a medieval English statute defining the length of the barleycorn, inch, foot, yard, and perch, as well as the area of the acre. Its ...
traditionally credited to
Edward I or
II, the statute foot was a different measure, exactly of the old (Belgic) foot. The
barleycorn,
inch
Measuring tape with inches
The inch (symbol: in or ″) is a unit of length in the British imperial and the United States customary systems of measurement. It is equal to yard or of a foot. Derived from the Roman uncia ("twelfth") ...
,
ell, and
yard
The yard (symbol: yd) is an English unit of length in both the British imperial and US customary systems of measurement equalling 3 feet or 36 inches. Since 1959 it has been by international agreement standardized as exactly 0.914 ...
were likewise shrunk, while
rods and
furlong
A furlong is a measure of distance in imperial units and United States customary units equal to one eighth of a mile, equivalent to 660 feet, 220 yards, 40 rods, 10 chains or approximately 201 metres. It is now mostly confined to use in hors ...
s remained the same.
The ambiguity over the state of the
mile
The mile, sometimes the international mile or statute mile to distinguish it from other miles, is a British imperial unit and United States customary unit of distance; both are based on the older English unit of length equal to 5,280 English ...
was resolved by the 1593
Act against Converting of Great Houses into Several Tenements and for Restraint of Inmates and Inclosures in and near about the City of London and Westminster, which codified the
statute mile
The mile, sometimes the international mile or statute mile to distinguish it from other miles, is a British imperial unit and United States customary unit of distance; both are based on the older English unit of length equal to 5,280 English ...
as comprising 5,280 feet. The differences among the various physical standard yards around the world, revealed by increasingly powerful
microscope
A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisibl ...
s, eventually led to the 1959 adoption of the
international foot
The foot ( feet), standard symbol: ft, is a unit of length in the British imperial and United States customary systems of measurement. The prime symbol, , is a customarily used alternative symbol. Since the International Yard and Po ...
defined in terms of the meter.
Definition
International foot
The
international yard and pound
The international yard and pound are two units of measurement that were the subject of an agreement among representatives of six nations signed on 1 July 1959: the United States, United Kingdom, Canada, Australia, New Zealand, and South Africa. T ...
agreement of July 1959 defined the length of the international yard in the United States and countries of the
Commonwealth of Nations
The Commonwealth of Nations, simply referred to as the Commonwealth, is a political association of 56 member states, the vast majority of which are former territories of the British Empire. The chief institutions of the organisation are the Co ...
as exactly 0.9144
meter
The metre (British spelling) or meter (American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its prefi ...
s. Consequently (since a foot is one-third of a yard), the international foot is defined to be equal to exactly 0.3048 meters. This was 2
ppm shorter than the previous U.S. definition and 1.7 ppm longer than the previous British definition.
The 1959 agreement concluded a series of step-by-step events, set off in particular by the
British Standards Institution
The British Standards Institution (BSI) is the national standards body of the United Kingdom. BSI produces technical standards on a wide range of products and services and also supplies certification and standards-related services to business ...
's adoption of a scientific standard inch of 25.4
millimetre
330px, Different lengths as in respect to the electromagnetic spectrum, measured by the metre and its derived scales. The microwave is between 1 meter to 1 millimeter.
The millimetre (American and British English spelling differences#-re, -er, ...
s in 1930.
Symbol
The IEEE standard symbol for a foot is "ft".
In some cases, the foot is denoted by a
prime
A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways ...
, often approximated by an
apostrophe
The apostrophe ( or ) is a punctuation mark, and sometimes a diacritical mark, in languages that use the Latin alphabet and some other alphabets. In English, the apostrophe is used for two basic purposes:
* The marking of the omission of one o ...
, and the inch by a double prime; for example, 2feet 4 inches is sometimes denoted as 2′4″.
Imperial units
In
Imperial units
The imperial system of units, imperial system or imperial units (also known as British Imperial or Exchequer Standards of 1826) is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed thro ...
, the foot was defined as yard, with the yard being realized as a physical standard (separate from the standard meter). The yard standards of the different
Commonwealth
A commonwealth is a traditional English term for a political community founded for the common good. Historically, it has been synonymous with "republic". The noun "commonwealth", meaning "public welfare, general good or advantage", dates from the ...
countries were periodically compared with one another. The value of the United Kingdom primary standard of the yard was determined in terms of the meter by the
National Physical Laboratory in 1964 to be , implying a pre-1959 UK foot of .
The UK adopted the international yard for all purposes through the
Weights and Measures Act 1963
Weights and measures acts are acts of the British Parliament determining the regulation of weights and measures. It also refers to similar royal and parliamentary acts of the Kingdoms of England and Scotland and the medieval Welsh states. T ...
, effective January 1, 1964.
Survey foot
When the international foot was defined in 1959, a great deal of survey data was already available based on the former definitions, especially in the United States and in
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
. The small difference between the survey foot and the international foot would not be detectable on a survey of a small parcel, but becomes significant for mapping, or when the
state plane coordinate system
The State Plane Coordinate System (SPCS) is a set of 124 geographic zones or coordinate systems designed for specific regions of the United States. Each state contains one or more state plane zones, the boundaries of which usually follow county li ...
(SPCS) is used in the US, because the origin of the system may be hundreds of thousands of feet (hundreds of miles) from the point of interest. Hence the previous definitions continued to be used for surveying in the United States and India for many years, and are denoted survey feet to distinguish them from the international foot. The United Kingdom was unaffected by this problem, as the
retriangulation of Great Britain
__NOTOC__
The retriangulation of Great Britain was a triangulation project carried out between 1935 and 1962 that sought to improve the accuracy of maps made of Great Britain. Data gathered from the retriangulation replaced data gathered during ...
(1936–62) had been done in meters.
U.S. survey foot
In the United States, the foot was defined as 12 inches, with the inch being defined by the
Mendenhall Order
The Mendenhall Order marked a decision to change the fundamental standards of length and mass of the United States from the customary standards based on those of England to metric standards. It was issued on April 5, 1893, by Thomas Corwin Mend ...
of 1893 as 39.37 inches = 1 m (making a US foot exactly meters, approximately ). Out of 50 states and six other jurisdictions, 40 have legislated that surveying measures should be based on the U.S. survey foot, six have legislated that they be made on the basis of the international foot, and ten have not specified.
State legislation is also important for determining the conversion factor to be used for everyday land surveying and real estate transactions, although the difference (two
parts per million
In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they ...
) is of no practical significance given the precision of normal surveying measurements over short distances (usually much less than a mile).
The
National Institute of Standards and Technology
The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...
,
National Geodetic Survey
The National Geodetic Survey (NGS) is a List of federal agencies in the United States, United States federal agency that defines and manages a national coordinate system, providing the foundation for transportation and communication; mapping an ...
, and the
United States Department of Commerce
The United States Department of Commerce is an executive department of the U.S. federal government concerned with creating the conditions for economic growth and opportunity. Among its tasks are gathering economic and demographic data for bu ...
are phasing out the US survey foot beginning in 2023.
However, its relevance may persist, as the Federal Register Notice says:
:"The date of December 31, 2022, was selected to accompany the modernization of the National Spatial Reference System (NSRS) by
NOAA
The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...
's National Geodetic Survey (NGS). The reason for associating the deprecation of the U.S. survey foot with the modernization of the NSRS is that the biggest impact of the uniform adoption of the international foot will be for users of the NSRS, due to very large coordinate values currently given in U.S. survey feet in many areas of the U.S. Impacts related to the change to international feet will be minimized if a transition occurs concurrently with others changes in the NSRS."
:"The difference will have no effect on users of the existing NSRS (National Spatial Reference System), because NGS (
NOAA
The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...
's National Geodetic Survey) ''will continue to support the U.S. survey foot for components of the NSRS where it is used now and in the past.'' In other words, to minimize disruption in the use of U.S. survey foot for existing NSRS coordinate systems, the change will apply only to the modernized NSRS."
Indian survey foot
The Indian survey foot is defined as exactly , presumably derived from a measurement of the previous Indian standard of the yard. The current National Topographic Database of the
Survey of India
The Survey of India is India's central engineering agency in charge of Cartography, mapping and surveying. is based on the metric
WGS-84
The World Geodetic System (WGS) is a standard used in cartography, geodesy, and satellite navigation including GPS. The current version, WGS 84, defines an Earth-centered, Earth-fixed coordinate system and a geodetic datum, and also descri ...
datum
In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted. ...
, which is also used by the
Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
.
Historical use
Metric foot
An
ISO 2848
ISO 2848 (''Building construction – Modular coordination – Principles and rules)'' is an international standard for the construction industry that describes the aims of modular coordination and gives the rules to be used in establishing the di ...
measure of 3 basic modules (30 cm) is called a "
metric foot
ISO 2848 (''Building construction – Modular coordination – Principles and rules)'' is an international standard for the construction industry that describes the aims of modular coordination and gives the rules to be used in establishing the di ...
", but there were earlier distinct definitions of a metric foot during
metrication
Metrication or metrification is the act or process of converting to the metric system of measurement. All over the world, countries have transitioned from local and traditional units of measurement to the metric system. This process began in F ...
in France and Germany.
France
In 1799 the meter became the official unit of length in
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
. This was not fully enforced, and in 1812
Napoleon
Napoleon Bonaparte ; it, Napoleone Bonaparte, ; co, Napulione Buonaparte. (born Napoleone Buonaparte; 15 August 1769 – 5 May 1821), later known by his regnal name Napoleon I, was a French military commander and political leader who ...
introduced the system of ''
mesures usuelles Mesures usuelles (, ''customary measurements'') were a French system of measurement introduced by Napoleon I in 1812 to act as compromise between the metric system and traditional measurements. The system was restricted to use in the retail indust ...
'' which restored the traditional French measurements in the retail trade, but redefined them in terms of metric units. The foot, or ''pied métrique'', was defined as one third of a meter. This unit continued in use until 1837.
Germany
In southwestern Germany in 1806, the
Confederation of the Rhine
The Confederated States of the Rhine, simply known as the Confederation of the Rhine, also known as Napoleonic Germany, was a confederation of German client states established at the behest of Napoleon some months after he defeated Austria an ...
was founded and three different ''reformed feet'' were defined, all of which were based on the metric system:
*In
Hesse
Hesse (, , ) or Hessia (, ; german: Hessen ), officially the State of Hessen (german: links=no, Land Hessen), is a States of Germany, state in Germany. Its capital city is Wiesbaden, and the largest urban area is Frankfurt. Two other major histor ...
, the ''Fuß'' (foot) was redefined as 25 cm.
*In
Baden
Baden (; ) is a historical territory in South Germany, in earlier times on both sides of the Upper Rhine but since the Napoleonic Wars only East of the Rhine.
History
The margraves of Baden originated from the House of Zähringen. Baden is ...
, the ''Fuß'' was redefined as 30 cm.
*In the
Palatinate, the ''Fuß'' was redefined as being cm (as in France).
Other obsolete feet
Prior to the introduction of the metric system, many European cities and countries used the foot, but it varied considerably in length: the ''voet'' in
Ypres
Ypres ( , ; nl, Ieper ; vls, Yper; german: Ypern ) is a Belgian city and municipality in the province of West Flanders. Though
the Dutch name is the official one, the city's French name is most commonly used in English. The municipality co ...
, Belgium, was 273.8 millimeters (10.78in) while the piede in Venice was 347.73 millimeters (13.690in). Lists of conversion factors between the various units of measure were given in many European reference works including:
*Traité,
Paris
Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...
– 1769
*Palaiseau –
Bordeaux
Bordeaux ( , ; Gascon oc, Bordèu ; eu, Bordele; it, Bordò; es, Burdeos) is a port city on the river Garonne in the Gironde department, Southwestern France. It is the capital of the Nouvelle-Aquitaine region, as well as the prefectur ...
: 1816
*de Gelder,
Amsterdam
Amsterdam ( , , , lit. ''The Dam on the River Amstel'') is the Capital of the Netherlands, capital and Municipalities of the Netherlands, most populous city of the Netherlands, with The Hague being the seat of government. It has a population ...
and
The Hague
The Hague ( ; nl, Den Haag or ) is a city and municipality of the Netherlands, situated on the west coast facing the North Sea. The Hague is the country's administrative centre and its seat of government, and while the official capital of ...
– 1824
*Horace,
Brussels
Brussels (french: Bruxelles or ; nl, Brussel ), officially the Brussels-Capital Region (All text and all but one graphic show the English name as Brussels-Capital Region.) (french: link=no, Région de Bruxelles-Capitale; nl, link=no, Bruss ...
– 1840
*Noback & Noback (2 volumes),
Leipzig
Leipzig ( , ; Upper Saxon: ) is the most populous city in the German state of Saxony. Leipzig's population of 605,407 inhabitants (1.1 million in the larger urban zone) as of 2021 places the city as Germany's eighth most populous, as wel ...
– 1851
*Bruhns, Leipzig – 1881
Many of these standards were peculiar to a particular city, especially in Germany (which, before
German Unification
The unification of Germany (, ) was the process of building the modern German nation state with federal features based on the concept of Lesser Germany (one without multinational Austria), which commenced on 18 August 1866 with adoption of t ...
in 1871, consisted of many kingdoms, principalities, free cities and so on). In many cases the length of the unit was not uniquely fixed: for example, the English foot was stated as 11 ''pouces'' 2.6 ''lignes'' (
French inches and lines) by
Picard, 11 ''pouces'' 3.11 ''lignes'' by
Maskelyne Maskelyne may refer to:
People
*Nevil Maskelyne (MP) (1711–1679), English landowner, MP for Cricklade
*Nevil Maskelyne (1732–1811), the fifth British Astronomer Royal
*Nevil Story Maskelyne (1823–1911), English geologist, MP for Cricklade
* ...
and 11 ''pouces'' 3 ''lignes'' by
D'Alembert
Jean-Baptiste le Rond d'Alembert (; ; 16 November 1717 – 29 October 1783) was a French mathematician, mechanician, physicist, philosopher, and music theorist. Until 1759 he was, together with Denis Diderot, a co-editor of the ''Encyclopédie ...
.
Most of the various feet in this list ceased to be used when the countries adopted the metric system. The Netherlands and modern Belgium adopted the metric system in 1817, having used the ''mesures usuelles'' under Napoleon and the newly formed
German Empire
The German Empire (),Herbert Tuttle wrote in September 1881 that the term "Reich" does not literally connote an empire as has been commonly assumed by English-speaking people. The term literally denotes an empire – particularly a hereditary ...
adopted the metric system in 1871.
The
palm
Palm most commonly refers to:
* Palm of the hand, the central region of the front of the hand
* Palm plants, of family Arecaceae
**List of Arecaceae genera
* Several other plants known as "palm"
Palm or Palms may also refer to:
Music
* Palm (ba ...
(typically 200 mm to 280 mm) was used in many Mediterranean cities instead of the foot. Horace Doursther, whose reference was published in Belgium which had the smallest foot measurements, grouped both units together, while J.F.G. Palaiseau devoted three chapters to units of length: one for linear measures (palms and feet); one for cloth measures (ells); and one for distances traveled (miles and leagues).
Obsolete feet details
In the table below, arbitrary cut-off points of 270 mm and 350 mm have been chosen.
In Belgium, the words ''pied'' (French) and ''voet'' (Dutch) would have been used interchangeably.
Notes
Present day uses
International ISO-standard and other intermodal shipping containers
International Standards Organisation
The International Organization for Standardization (ISO ) is an international standard development organization composed of representatives from the national standards organizations of member countries. Membership requirements are given in Art ...
(ISO)-defined intermodal containers
An intermodal container, often called a shipping container, is a large standardized shipping container, designed and built for intermodal freight transport, meaning these containers can be used across different modes of transport – from ship ...
for efficient global freight/cargo shipping, were defined using feet rather than meters for their leading outside (corner) dimensions. All ISO-standard containers to this day are eight feet wide, and their outer heights and lengths are also primarily defined in, or derived from feet.
Quantities of global shipping containers are still primarily counted in Twenty-foot Equivalent Unit
The twenty-foot equivalent unit (abbreviated TEU or teu) is an inexact unit of cargo capacity, often used for container ships and container ports.Rowlett, 2004. It is based on the volume of a intermodal container, a standard-sized metal box whic ...
s, or TEUs.
Aviation
Everyday global (civilian) air traffic / aviation continues to be controlled in flight level
In aviation and aviation meteorology, a flight level (FL) is an aircraft's altitude at standard air pressure, expressed in hundreds of feet. The air pressure is computed assuming an International Standard Atmosphere pressure of 1013.25 hPa ...
s (flying altitudes) separated by thousands of feet (although typically read out in hundreds - e.g. flight level 330 actually means 33,000 feet, or about 10 kilometres in altitude).
Dimension
In measurement, the term "linear foot" (sometimes incorrectly referred to as "lineal foot") refers to the number of feet in a length of material (such as lumber or fabric) without regard to the width; it is used to distinguish from surface area
The surface area of a solid object is a measure of the total area that the surface of the object occupies. The mathematical definition of surface area in the presence of curved surfaces is considerably more involved than the definition of arc ...
in ''square foot
The square foot (plural square feet; abbreviated sq. ft, sf, or ft2; also denoted by '2) is an imperial unit and U.S. customary unit (non- SI, non-metric) of area, used mainly in the United States and partially in Canada, the United Kingdom, Bang ...
''.
See also
* Anthropic units
The term anthropic unit (from Greek '' άνθρωπος'' meaning human) is used with different meanings in archaeology, in measurement and in social studies.
In archaeology
In archaeology, ''anthropic units'' are strata, or deposits of mater ...
* History of measurement
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 ap ...
* International System of Units
The International System of Units, known by the international abbreviation SI in all languages and sometimes pleonastically as the SI system, is the modern form of the metric system and the world's most widely used system of measurement. E ...
* Korean units of measurement
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 Jap ...
* Mermin's foot
* Pous
The pous ( podes; grc-gre, ποῦς, ''poûs'') or Greek foot ( feet) was a Greek unit of length. It had various subdivisions whose lengths varied by place and over time. 100 podes made up one plethron, 600 podes made up a stade (the G ...
* Systems of measurement
A system of measurement is a collection of units of measurement and rules relating them to each other. Systems of measurement have historically been important, regulated and defined for the purposes of science and commerce. Systems of measurement i ...
Notes
References
{{DEFAULTSORT:Foot
Customary units of measurement in the United States
Human-based units of measurement
Imperial units
Units of length