Foot (unit)

{{Short description|Customary unit of length}}
{{About|the unit of measure|sizing of the human foot|Shoe size|other uses|Foot (disambiguation)}}
{{Use mdy dates|date=October 2022}}
{{Use American English|date=April 2020}}
{{Infobox unit
| name     = foot
| image    = SCALE.jpg
| caption  = A foot-long ruler
| symbol   = ft
| symbol2  = ′
| standard = [[Imperial units|Imperial]]/[[US customary units|US]] units
| quantity = [[Length]]
| units2   = [[Metric system|Metric]] ([[SI]]) units
| inunits2 = {{ubl | 0.3048&nbsp;[[Metre|m]] | 30.48 [[centimeters|cm]] | 304.8 [[millimeters|mm]]}}
| units1   = Imperial/US units
| inunits1 = {{ubl | {{sfrac|3}}&nbsp;[[Yard|yd]] | 12&nbsp;[[Inch|in]]}}
}}
The '''foot''' ({{plural form|'''feet'''}}; standard symbol: '''ft''')<ref name=IEEE /><ref>{{cite book |title=BS350:Part 1:1974 Conversion factors and tables Part 1. Basis of tables. Conversion factors |date=1974 |publisher=British Standards Institution |pages=5, 91}}</ref> is a [[Units of measurement|unit]] of [[length]] in the [[imperial units|British imperial]] and [[United States customary units|United States customary]] systems of [[metrology|measurement]]. The [[prime (symbol)|prime symbol]], {{char|′}}, is commonly used to represent the foot.<ref>{{cite book| title = Chicago Manual of Style | edition = 17th | date = 2017 | publisher = University of Chicago Press | at = ¶ 10.66}}</ref> In both customary and imperial units, one foot comprises 12&nbsp;[[inch]]es, and one [[yard]] comprises three feet. Since [[international yard and pound|an international agreement in 1959]], the foot is  defined as equal to exactly 0.3048 meters. 

Historically, the "foot" was a part of many local systems of units, including the [[Ancient Greek units of measurement|Greek]], [[Ancient Roman units of measurement|Roman]], [[Chinese units of measurement|Chinese]], [[Units of measurement in France before the French Revolution|French]], and [[English units|English]] 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&nbsp;mm and 335&nbsp;mm and was generally, but not always, subdivided into 12&nbsp;inches or 16&nbsp;[[digit (unit)|digit]]s.

The United States is the only industrialized country that uses the (international) foot in preference to the meter in its commercial, engineering, and standards activities.<ref name="World Factbook">{{Cite book |chapter-url=https://www.cia.gov/library/publications/the-world-factbook/appendix/appendix-g.html |title=The World Factbook |date=January 17, 2007 |publisher=Washington: [[Central Intelligence Agency]] |chapter=Appendix G – Weights and Measures |access-date=February 4, 2007 |url-status=live |archive-url=http://archive.wikiwix.com/cache/20110223164402/https://www.cia.gov/library/publications/the-world-factbook/appendix/appendix-g.html |archive-date=February 23, 2011  }}</ref> The foot is legally recognized in the United Kingdom; road distance signs ''must'' use imperial units (however, distances on road signs are always marked in miles or yards, not feet; bridge clearances are given in meters as well as feet and inches), while its usage is widespread among the British public as a measurement of height.<ref>{{cite news|title=Will British people ever think in metric?|url=https://www.bbc.co.uk/news/magazine-16245391|publisher=BBC|date=December 21, 2011|first1=Jon|last1=Kelly|url-status=live|archive-url=https://web.archive.org/web/20120424232814/http://www.bbc.co.uk/news/magazine-16245391|archive-date=April 24, 2012}}</ref><ref>Alder, Ken (2002). The Measure of all Things—The Seven-Year-Odyssey that Transformed the World. London: Abacus.</ref> The foot is recognized as an alternative expression of length in Canada.<ref>''[http://laws-lois.justice.gc.ca/eng/acts/W-6/page-2.html#h-4/ Weights and Measures Act]'' {{webarchive|url=https://web.archive.org/web/20141228014049/http://laws-lois.justice.gc.ca/eng/acts/W-6/page-2.html |date=December 28, 2014 }}, accessed January 2012, Act current to January 18, 2012.  Basis for units of measurement 4.(1) All units of measurement used in Canada shall be determined on the basis of the International System of Units established by the General Conference of Weights and Measures. (...) Canadian units (5) The Canadian units of measurement are as set out and defined in Schedule II, and the symbols and abbreviations therefore are as added pursuant to subparagraph 6(1)(b)(ii).</ref> Both the UK and Canada have partially [[Metrication|metricated]] their units of measurement. The measurement of [[altitude#Aviation|altitude]] in international [[aviation]] (the [[flight level]] unit) is one of the few areas where the foot is used outside the English-speaking world.

==Historical origin==
{{See also|pous}}
[[File:Determination of the rute and the feet in Frankfurt.png|thumb|Determination of the rod, using the length of the left foot of 16 randomly chosen people coming from church service. Woodcut published in the book {{lang|de|Geometrey}} by [[Jakob Köbel]] (Frankfurt, {{c.|1535}}).]]
Historically, the human body has been used to provide the basis for units of length.<ref name="Dilke1987-23">{{cite book|author=Oswald Ashton Wentworth Dilke|author-link=Oswald A.W. Dilke|title=Mathematics and measurement|url=https://archive.org/details/bub_gb_AKJZvXOS7n4C|access-date=February 2, 2012|date=May 22, 1987|publisher=University of California Press|isbn=978-0-520-06072-2|page=[https://archive.org/details/bub_gb_AKJZvXOS7n4C/page/n23 23]}}</ref> The foot of an adult European-American male is typically about 15.3% of his height,<ref>{{cite journal
 |url         = http://www.sscnet.ucla.edu/anthro/faculty/fessler/pubs/AHBFootSizeDimorphism.pdf
 |title       = Sexual dimorphism in foot length proportionate to stature
 |first1      = Daniel M
 |last1       = Fessler
 |first2      = Kevin J
 |last2       = Haley
 |first3      = Roshni D
 |last3       = Lal
 |journal     = Annals of Human Biology
 |date        = January–February 2005
 |volume      = 32
 |issue       = 1
 |pages       = 44–59
 |doi         = 10.1080/03014460400027581
 |pmid = 15788354
 |s2cid = 194735
 |url-status  = dead
 |archive-url  = https://web.archive.org/web/20110608084140/http://www.sscnet.ucla.edu/anthro/faculty/fessler/pubs/AHBFootSizeDimorphism.pdf
 |archive-date = June 8, 2011
|df          = mdy-all
}}</ref> giving a person of {{convert|175|cm|ftin|abbr=on}} a foot-length of about {{convert|268|mm|abbr=on}}, on average.<!-- Stature chosen here as that of average Caucasian male. Edge cases may have too many other anomalies to be useful. -->

Archaeologists believe that, in the past, the people of [[Ancient Egyptian units of measurement|Egypt]], [[Indian units of measurement|India]], and [[Ancient Mesopotamian units of measurement|Mesopotamia]] preferred the [[cubit]], while the people of [[Ancient Rome|Rome]], [[Ancient Greece|Greece]], and [[Chinese units of measurement|China]] preferred the foot. Under the Harappan linear measures, Indus cities during the Bronze Age used a foot of {{convert|13.2|in|0}} and a cubit of {{convert|20.8|in|0}}.<ref>Kenoyer JM (2010) "Measuring the Harappan world," in Morley I & Renfrew C (edd) The Archaeology of Measurement, 117; {{cite web |url=http://a.harappa.com/sites/g/files/g65461/f/Kenoyer%202010%20Measuring%20the%20Harappan%20World.pdf |title=Archived copy |access-date=January 11, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150626134828/http://a.harappa.com/sites/g/files/g65461/f/Kenoyer%202010%20Measuring%20the%20Harappan%20World.pdf |archive-date=June 26, 2015  }}</ref> The [[Ancient Egyptian units of measurement|Egyptian]] equivalent of the foot—a measure of four palms or 16 digits—was known as the {{lang|egy-Latn|djeser}} and has been reconstructed as about {{convert|30|cm|abbr=on|1}}.

The Greek foot ({{lang|grc|πούς}}, {{lang|grc-Latn|pous}}) had a length of {{sfrac|600}} of a [[Stadion (unit of length)|stadion]],<ref>{{cite web|url=https://archive.org/details/historyofherod02hero|title=History of Herodotus : a new English version|last1=Herodotus|first2=George|last2=Rawlinson|date=May 14, 1861|publisher=New York D. Appleton|via=Internet Archive}}</ref> one stadion being about {{convert|181.2|m|abbr=on}};<ref>{{cite web|url=https://www.perseus.tufts.edu/hopper/artifact?name=Epidauros,+Stadium&object=Building|title=Epidauros, Stadium (Building)|website=www.perseus.tufts.edu|url-status=live|archive-url=https://web.archive.org/web/20170510073158/http://www.perseus.tufts.edu/hopper/artifact?name=Epidauros%2C+Stadium&object=Building|archive-date=May 10, 2017}}</ref> therefore a foot was, at the time, about {{convert|302|mm|abbr=on|1}}. Its exact size varied from city to city and could range between {{convert|270|mm|abbr=on|1}} and {{convert|350|mm|abbr=on|1}}, but lengths used for temple construction appear to have been about {{convert|295|mm|abbr=on|1}} to {{convert|325|mm|abbr=on|1}}; the former was close to the size of the Roman foot.

The standard [[Roman foot]]  ({{lang|la|pes}}) was normally about {{convert|295.7|mm|abbr=on|1}} (97% of today's measurement),<ref name=brit>Hosch, William L. (ed.) (2010) [https://books.google.com/books?id=cuN7rH6RzikC ''The Britannica Guide to Numbers and Measurement''] New York, NY: Britannica Educational Publications, 1st edition. {{ISBN|978-1-61530-108-9}}, p.206</ref> but in some provinces, particularly [[Germania Inferior]], the so-called {{lang|la|pes Drusianus}} (foot of [[Nero Claudius Drusus]]) was sometimes used, with a length of about {{convert|334|mm|abbr=on|1}}. (In reality, this foot predated Drusus.)<ref name="Dilke1987-26">{{cite book|author=Oswald Ashton Wentworth Dilke|author-link=Oswald A.W. Dilke|title=Mathematics and measurement|url=https://archive.org/details/bub_gb_AKJZvXOS7n4C|access-date=February 2, 2012|date=May 22, 1987|publisher=University of California Press|isbn=978-0-520-06072-2|page=[https://archive.org/details/bub_gb_AKJZvXOS7n4C/page/n26 26]}}</ref><ref>{{Cite journal |last=Duncan-Jones |first=R. P. |date=1980 |title=Length-Units in Roman Town Planning: The Pes Monetalis and the Pes Drusianus |url=https://www.jstor.org/stable/525675 |journal=Britannia |volume=11 |pages=127–133 |doi=10.2307/525675|jstor=525675 |s2cid=164149478 }}</ref>

Originally both the Greeks and the Romans subdivided the foot into 16 [[Digit (unit)|digits]], but in later years, the Romans also subdivided the foot into 12 {{lang|la|unciae}} (from which both the English words "inch" and "[[ounce]]" are derived).

After the fall of the Roman Empire, some Roman traditions were continued but others fell into disuse. In AD 790 [[Charlemagne]] attempted to reform the units of measure in his domains. His units of length were based on the {{lang|fr|[[toise]]}} and in particular the {{lang|fr|toise de l'Écritoire}}, the distance between the fingertips of the outstretched arms of a man.<ref>{{cite web
 |url         = http://www.unc.edu/~rowlett/units/dictT.html
 |author      = Russ Rowlett
 |publisher   = Center for Mathematics and Science Education, [[University of North Carolina at Chapel Hill]]
 |title       = How Many? A Dictionary of Units of Measurement
 |access-date  = February 28, 2011
|url-status     = live
 |archive-url  = https://web.archive.org/web/20121224005450/http://www.unc.edu/~rowlett/units/dictT.html
 |archive-date = December 24, 2012
|df          = mdy-all
}}</ref> The {{lang|fr|toise}} has 6 {{lang|fr|pieds}} (feet) each of {{convert|326.6|mm|abbr=on|1}}.

He was unsuccessful in introducing a standard unit of length throughout his realm: an analysis of the measurements of [[Charlieu Abbey]] shows that during the 9th century the Roman foot of {{convert|296.1|mm|abbr=on}} was used; when it was rebuilt in the 10th century, a foot of about {{convert|320|mm|abbr=on|1}}<ref group = "Note" name="cm">The original reference was given in a round number of centimeters.</ref> was used. At the same time, monastic buildings used the Carolingian foot of {{convert|340|mm|abbr=on|1}}.<ref group = "Note" name="cm"/><ref>{{cite journal
|jstor = 987740
|first = Elizabeth R
|last = Sutherland
|journal = Journal of the Society of Architectural Historians
|title = Feet and dates at Charlieu
|date = May 1957
|volume = 16
|issue = 2|pages = 2–5
|doi = 10.2307/987740
}}</ref>

The procedure for verification of the foot as described in the 16th century posthumously published work by [[Jacob Köbel]] in his book {{lang|de|Geometrei. Von künstlichem Feldmessen und absehen}} is:<ref>{{cite book
 |url         = http://www.robweir.com/blog/2007/12/right-and-lawful-rood.html
 |title       = Geometrei. Von künstlichem Feldmessen und absehen
 |year        = 1535
 |author      = Jacob Koebel
 |language    = de
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20111116021207/http://www.robweir.com/blog/2007/12/right-and-lawful-rood.html
 |archive-date = November 16, 2011
|df          = mdy-all
 |author-link = Jacob Koebel
}}</ref><ref>{{cite web |title=Geometrey |url=https://digital.slub-dresden.de/werkansicht/dlf/8082/1/cache.off |website=digital.slub-dresden.de |publisher=Saxon State Library |access-date=February 22, 2019 |language=de-DE}}</ref>
{{blockquote|Stand at the door of a church on a Sunday and bid 16 men to stop, tall ones and small ones, as they happen to pass out when the service is finished; then make them put their left feet one behind the other, and the length thus obtained shall be a right and lawful [[Rood (unit)#Linear measure|rood]] to measure and survey the land with, and the 16th part of it shall be the right and lawful foot.}}

===England===
[[File:Imperial measurement standards, Greenwich.JPG|thumb|The unofficial public [[imperial units|imperial measurement]] [[standard (metrology)|standards]] erected at the [[Royal Observatory, Greenwich|Royal Observatory]] in [[Greenwich, England|Greenwich]] in the 19th century]]
{{See also|Yard}}

The [[Neolithic]] '''long foot''', first proposed by archeologists [[Mike Parker Pearson]] and Andrew Chamberlain, is based upon calculations from surveys of [[Stonehenge#Stonehenge 1 (c. 3100 BC)|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|international foot]] (thus 12.672 inches or 0.3219 m). Furthermore, this unit is identifiable in the dimensions of some stone [[lintels]] at the site and in the diameter of the "southern circle"  at nearby [[Durrington Walls]]. Evidence that this unit was in widespread use across southern Britain is available from the [[Folkton Drums]] from  [[Yorkshire]] ([[neolithic]] artifacts, made from chalk, with circumferences that exactly divide as [[integers]] into ten long feet) and a similar object, the [[Lavant drum]], excavated at [[Lavant, West Sussex|Lavant]], Sussex, again with a circumference divisible as a whole number into ten long feet.<ref>{{cite journal |last1=Teather |first1=Anne |display-authors=etal|title=Getting the Measure of Stonehenge |journal=[[British Archaeology]] |date=February 8, 2019 |issue=165 |pages=48–51}}</ref>

The measures of [[Iron Age Britain]] are uncertain and proposed reconstructions such as the [[Megalithic Yard]] are controversial. Later [[Welsh legend]] credited [[Dyfnwal Moelmud]] with the establishment of [[Welsh units|their units]], including a foot of 9 inches. The Belgic or North German foot of {{convert|335|mm|abbr=on|1}} was introduced to England either by the [[Belgae|Belgic Celts]] during their invasions prior to the Romans or by the [[Anglo-Saxons]] in the 5th and 6th century.

[[Roman units]] were introduced following [[Roman conquest of England|their invasion]] in AD&nbsp;43. Following the [[Roman withdrawal from Britain|Roman withdrawal]] and [[Saxon invasion of England|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 (unit)|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]] and then [[London]]. [[Henry I of England|Henry I]] was said to have ordered a new standard to be based upon the length of his own arm and, by the {{circa|lk=no|1300}} Act concerning the [[Composition of Yards and Perches]]<ref name="Britain1762">{{cite book|author=Great Britain|title=The statutes at large: from the Magna Charta, to the end of the eleventh Parliament of Great Britain, anno 1761 (continued to 1807)|url=https://books.google.com/books?id=iPQuAAAAIAAJ&q=Compositio+ulnarum+et+perticarum&pg=PA400|access-date=November 30, 2011|volume=1|year=1762|publisher=Printed by J. Bentham|page=400}}</ref> traditionally credited to [[Edward I of England|Edward&nbsp;I]] or [[Edward II of England|II]], the statute foot was a different measure, exactly {{sfrac|10|11}} of the old (Belgic) foot. The [[barleycorn (unit)|barleycorn]], [[inch]], [[ell (unit)|ell]], and [[yard]] were likewise shrunk, while [[rod (unit)|rod]]s and [[furlong]]s remained the same.<ref name="1977zupko">{{cite book | last = Zupko | first = Ronald Edward | author-link = Ronald Edward Zupko | title = British Weights and Measures: A History from Antiquity to the Seventeenth Century | publisher=University of Wisconsin Press | year = 1977 | isbn = 978-0-299-07340-4 | pages = 6, 10, 20 | url = https://books.google.com/books?id=pWUgAQAAIAAJ }}</ref> The ambiguity over the state of the [[mile]] 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]] as comprising 5,280&nbsp;feet. The differences among the various physical standard yards around the world, revealed by increasingly powerful [[microscope]]s, eventually led to the 1959 adoption of the [[#International foot|international foot]] defined in terms of the meter.

==Definition==

===International foot===
The [[international yard and pound]] agreement of July 1959 defined the length of the international yard in the United States and countries of the [[Commonwealth of Nations]] as exactly 0.9144 [[meter]]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&nbsp;[[Parts per million|ppm]] shorter than the previous US definition and 1.7&nbsp;ppm longer than the previous British definition.<ref>{{cite web
 |url         = http://www.npl.co.uk/reference/faqs/on-what-basis-is-one-inch-exactly-equal-to-25.4-mm-has-the-imperial-inch-been-adjusted-to-give-this-exact-fit-and-if-so-when-(faq-length)
 |publisher   = [[National Physical Laboratory (United Kingdom)|National Physical Laboratory]]
 |title       = On what basis is one inch exactly equal to 25.4 mm? Has the imperial inch been adjusted to give this exact fit and if so when?
 |access-date  = July 24, 2012
|url-status  = dead
 |archive-url  = https://web.archive.org/web/20120807195334/http://www.npl.co.uk/reference/faqs/on-what-basis-is-one-inch-exactly-equal-to-25.4-mm-has-the-imperial-inch-been-adjusted-to-give-this-exact-fit-and-if-so-when-(faq-length)
 |archive-date = August 7, 2012
|df          = mdy-all
}}</ref>

The 1959 agreement concluded a series of step-by-step events, set off in particular by the [[British Standards Institution]]'s adoption of a scientific standard inch of 25.4 [[millimetre]]s in 1930.

====Symbol====
The IEEE standard symbol for a foot is "ft".<ref name=IEEE>{{cite web |title=Recommended Unit Symbols, SI Prefixes, and Abbreviations|url=https://www.ewh.ieee.org/soc/ias/pub-dept/abbreviation.pdf|access-date=April 7, 2021}}</ref> In some cases, the foot is denoted by a [[Prime (symbol)|prime]], often approximated by an [[apostrophe]], and the inch by a double prime; for example, 2{{nbsp}}feet 4&nbsp;inches is sometimes denoted as 2′{{nbsp}}4″.<ref name=CMOS>{{cite book| title = Chicago Manual of Style | edition = 17th | date = 2017 | publisher = University of Chicago Press | at = ¶ 10.66}}</ref>

=== Imperial units ===
In [[Imperial units]], the foot was defined as {{sfrac|1|3}}&nbsp;yard, with the yard being realized as a physical standard (separate from the standard meter). The yard standards of the different [[Commonwealth of Nations|Commonwealth]] countries were periodically compared with one another.<ref>See, for example, ''Report on the Comparisons of the Parliamentary Copies of the Imperial Standards with the Imperial Standard Yard and the Imperial Standard Pound and with each other during the Years 1947 to 1948'' (H.M.S.O., London, 1950). ''Report on the Comparisons of the Parliamentary Copies of the Imperial Standards with each other during the Year 1957'' (H.M.S.O., London, 1958).</ref> The value of the United Kingdom primary standard of the yard was determined in terms of the meter by the [[National Physical Laboratory (United Kingdom)|National Physical Laboratory]] in 1964 to be {{val|0.9143969|u=m}},<ref>{{cite journal |author1=Bigg, P. H. |author2=Anderton, Pamela |date=March 1964 |title=The United Kingdom standards of the yard in terms of the meter |url=http://www.iop.org/EJ/abstract/0508-3443/15/3/308/ |url-status=dead |journal=British Journal of Applied Physics |volume=15 |issue=3 |pages=291–300 |doi=10.1088/0508-3443/15/3/308 |bibcode=1964BJAP...15..291B |archive-url=https://archive.today/20120803014104/http://iopscience.iop.org/0508-3443/15/3/308 |archive-date=August 3, 2012 |access-date=May 16, 2009 }}</ref> implying a pre-1959 UK foot of {{val|0.3047990|u=m}}.

The UK adopted the international yard for all purposes through the [[Weights and Measures Act 1963]], effective January 1, 1964.<ref>[http://www.bailii.org/ew/cases/EWHC/Admin/2002/195.html Thoburn v Sunderland City Council &#91;2002&#93; EWHC 195 (Admin) (18 February 2002)]</ref>

===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]]. 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|state plane coordinate system]] (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]] (1936–62) had been done in meters.

====US survey foot{{anchor|United States survey foot}}====
In the United States, the foot was defined as 12&nbsp;inches, with the inch being defined by the [[Mendenhall Order]] of 1893 as 39.37&nbsp;inches&nbsp;= 1&nbsp;m (making a US foot exactly {{sfrac|1200|3937}}{{nbsp}}meters, approximately {{val|0.30480061|u=m}}).{{r|NYT 2020-08-18}}<ref>A. V. Astin & H. Arnold Karo (1959). [http://www.ngs.noaa.gov/PUBS_LIB/FedRegister/FRdoc59-5442.pdf "Refinement of values for the yard and the pound"]. {{webarchive|url=https://web.archive.org/web/20060821223520/http://www.ngs.noaa.gov/PUBS_LIB/FedRegister/FRdoc59-5442.pdf |date=August 21, 2006 }}. Washington DC: National Bureau of Standards. Republished on National Geodetic Survey web site and the Federal Register (Doc. 59-5442, filed June 30, 1959)</ref> Out of 50 states and six other jurisdictions, 40 have legislated that surveying measures should be based on the US survey foot, six have legislated that they be made on the basis of the international foot, and ten have not specified.<ref>[https://www.ngs.noaa.gov/SPCS/maps.shtml#spcs83 "State Plane Coordinate System"], National Geodetic Survey, May 4, 2019.</ref>

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]]) 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]], [[National Geodetic Survey]], and the [[United States Department of Commerce]] are phasing out the US survey foot beginning in 2023.<ref>{{Cite web| title = U.S. Survey Foot| work = National Institute of Standards and Technology| access-date = 2024-04-04| date = 2023-01-04| url = https://www.nist.gov/pml/us-surveyfoot}}</ref><ref>[https://www.ngs.noaa.gov/web/news/measure-unit-change-coming.shtml "Measuring Unit Change Coming in 2022"], National Geodetic Survey, June 14, 2019.</ref><ref name="NYT 2020-08-18">{{Cite news|last=Mitchell|first=Alanna|date=August 18, 2020|title=America Has Two Feet. It's About to Lose One of Them|language=en-US|work=The New York Times|url=https://www.nytimes.com/2020/08/18/science/foot-surveying-metrology-dennis.html|access-date=August 19, 2020|issn=0362-4331}}</ref> However, its relevance may persist, as the Federal Register Notice says:<ref>{{cite web | url=https://www.federalregister.gov/documents/2020/10/05/2020-21902/deprecation-of-the-united-states-us-survey-foot | website=Federal Register |title=Deprecation of the United States (U.S.) Survey Foot |date=October 5, 2020}}</ref>

{{quote|
The date of December 31, 2022, was selected to accompany the modernization of the National Spatial Reference System (NSRS) by [[National Oceanic and Atmospheric Administration|NOAA]]'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 {{sic|others}} changes in the NSRS. ...

The difference in timelines will have no effect on users of the existing NSRS (National Spatial Reference System), because NGS ([[National Oceanic and Atmospheric Administration|NOAA]]'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'' [emphasis added]. 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 {{val|0.3047996|u=m}},<ref>Schedule to the [https://web.archive.org/web/20091112174359/http://202.54.104.236/intranet/eip/legislation/uploads/THE%20STANDARDS%20OF%20WEIGHTS%20AND%20MEASURES%20ACT%201976.pdf Standards of Weights and Measures Act, 1976].</ref> presumably derived from a measurement of the previous Indian standard of the yard. The current National Topographic Database of the [[Survey of India]] is based on the metric [[WGS-84]] [[datum (geodesy)|datum]],<ref>[[Survey of India]], [http://www.surveyofindia.gov.in/tenders/nationalmappolicy/nationalmappolicy.pdf "National Map Policy – 2005"] {{webarchive|url=https://web.archive.org/web/20100331035549/http://www.surveyofindia.gov.in/tenders/nationalmappolicy/nationalmappolicy.pdf |date=March 31, 2010 }}.</ref> which is also used by the [[Global Positioning System]].

==Historical use==
[[Image:Fußmaße1.jpg|thumbnail|250px|Page from Austrian ''Lehrbuch des gesammten Rechnens für die vierte Classe der Hauptschulen in den [[k.k.]] Staaten'' – 1848<ref name=book>Dr. Franz Mozhnik: ''Lehrbuch des gesammten Rechnens für die vierte Classe der Hauptschulen in den k.k. Staaten.'' Im Verlage der k.k. Schulbücher Verschleiß-Administration bey St. Anna in der Johannisgasse – Wien 1848</ref> (Combined mathematics textbook for the fourth form of senior schools in the [[Imperial–royal]] states.)]]

===Metric foot===

An [[ISO 2848]] measure of 3 basic modules (30&nbsp;cm) is called a "[[metric foot]]",{{Cn|date=May 2023|reason=this association with ISO 2848 needs sourcing}} but there were earlier distinct definitions of a metric foot during [[metrication]] in France and Germany.

====France====

In 1799 the metre became the official unit of length in [[France]]. This was not fully enforced, and in 1812 [[Napoleon]] introduced the system of ''[[mesures usuelles]]'' 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 metre. This unit continued in use until 1837.<ref name="historique">{{cite web
 |url         = http://www.industrie.gouv.fr/metro/aquoisert/metre.htm
 |title       = Un historique du mètre
 |language    = fr
 |author      = Denis Février
 |publisher   = Ministère de l'Économie, des Finances et de l'Industrie
 |access-date  = March 10, 2011
|url-status  = live
 |archive-url  = https://web.archive.org/web/20110228185545/http://www.industrie.gouv.fr/metro/aquoisert/metre.htm
 |archive-date = February 28, 2011
|df          = mdy-all
}}</ref>

====Germany====

In southwestern Germany in 1806, the [[Confederation of the Rhine]] was founded and three different ''reformed feet'' were defined, all of which were based on the metric system:<ref name="DE1842">{{cite web
 |url         = http://www.spasslernen.de/geschichte/groessen/mas4.htm
 |language    = de
 |title       = Amtliche Maßeinheiten in Europa 1842
 |trans-title = Official measures in Europe 1842
 |access-date  = September 22, 2012
|url-status  = live
 |archive-url  = https://web.archive.org/web/20130723074500/http://www.spasslernen.de/geschichte/groessen/mas4.htm
 |archive-date = July 23, 2013
|df          = mdy-all
}}</ref>
*In [[Hesse]], the ''Fuß'' (foot) was redefined as 25&nbsp;cm.
*In [[Baden]], the ''Fuß'' was redefined as 30&nbsp;cm.
*In the [[Palatinate (region)|Palatinate]], the ''Fuß'' was redefined as being {{sfrac|33|1|3}}&nbsp;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 {{lang|nl|voet}} in [[Ypres]], Belgium, was 273.8 millimeters (10.78{{nbsp}}in) while the {{lang|vec|piede}} in Venice was 347.73 millimeters (13.690{{nbsp}}in). Lists of conversion factors between the various units of measure were given in many European reference works including:
*Traité, [[Paris]] – 1769<ref name="Traite">{{cite book
|url = https://books.google.com/books?id=eAkOAAAAQAAJ
|title = Traité des mesures itinéraires anciennes et modernes
|language = fr
|trans-title= Treatise of ancient and modern measures of distance
|last = d'Anville
|first = Jean Baptiste Bourguignon
|year = 1769
|location = Paris
|publisher = de l'Imprimerie Royale
|access-date =October 24, 2011 }}</ref>
*Palaiseau – [[Bordeaux]]: 1816 <ref name="Palaiseau">{{cite book
|url = https://books.google.com/books?id=ahjPAAAAMAAJ
|title = Métrologie universelle, ancienne et moderne: ou rapport des poids et mesures des empires, royaumes, duchés et principautés des quatre parties du monde
|first = JFG
|last = Palaiseau
|location = Bordeaux
|date = October 1816
|access-date =October 30, 2011}}</ref>
*de Gelder, [[Amsterdam]] and [[The Hague]] – 1824<ref name="NL2">{{cite book
|url = https://archive.org/details/allereerstegron00ramagoog
|title = Allereerste Gronden der Cijferkunst
|author = Jacob de Gelder
|location = 's-Gravenhage (The Hague) and Amsterdam
|language = nl
|year = 1824
|pages = [https://archive.org/details/allereerstegron00ramagoog/page/n372 163]–176
|publisher = de Gebroeders van Cleef
|trans-title = Introduction to Numeracy
|access-date =March 2, 2011}}</ref>
*Horace, [[Brussels]] – 1840<ref name="Horace">{{cite book
|title =  Dictionnaire universel des poids et mesures anciens et modernes
|first = Horace
|last = Doursther
|location = Brussels
|publisher = M. Hayez
|access-date =October 25, 2011
|year = 1840
|url = https://archive.org/details/dictionnaireuni00dourgoog
|quote =  liege.
|pages = [https://archive.org/details/dictionnaireuni00dourgoog/page/n416 402]–418
}}</ref>
*Noback & Noback (2 volumes), [[Leipzig]] – 1851<ref name="DE1851">{{cite book
|url = https://books.google.com/books?id=AkhTAAAAMAAJ
|title = Vollständiges tasehenbuch der Münz-, Maass- und Gewichts-Verhältnisse etc. aller Länder und Handelsplätze
|language = de
|trans-title = Comprehensive pocketbook of money, weights and measures for all counties and trading centres
|first1 = Christian
|last1 = Noback
|first2 = Friedrich Eduard
|last2 = Noback
|year = 1851
|volume = I
|location = Leipzig
|publisher = F. А. Brockhaus
|access-date =October 24, 2011
}}</ref><ref name="DE1851V2">{{cite book
|url = https://books.google.com/books?id=KEpTAAAAMAAJ
|title = Vollständiges tasehenbuch der Münz-, Maass- und Gewichts-Verhältnisse etc. aller Länder und Handelsplätze
|language = de
|trans-title = Comprehensive pocketbook of money, weights and measures for all counties and trading centres
|first1 = Christian
|last1 = Noback
|first2 = Friedrich Eduard
|last2 = Noback
|year = 1851
|volume = II
|location = Leipzig
|publisher = F. А. Brockhaus
|access-date =October 24, 2011
}}</ref>
*Bruhns, Leipzig – 1881<ref name="Bruhns">{{cite book
|url = https://books.google.com/books?id=GoMNAQAAIAAJ
|title = new manual of logarithms to seven places of decimals
|page = 610
|first = Carl
|last = Bruhns
|publisher = Bernhard Tauchnitz
|location = Leipzig
|year = 1881
|access-date = October 26, 2011
}}</ref>

Many of these standards were peculiar to a particular city, especially in Germany (which, before [[German unification]] 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'' ([[Units of measurement in France before the French Revolution|French inches and lines]]) by [[Jean Picard|Picard]], 11 ''pouces'' 3.11 ''lignes'' by [[Nevil Maskelyne|Maskelyne]], and 11 ''pouces'' 3 ''lignes'' by [[Jean le Rond d'Alembert|D'Alembert]].<ref>{{cite web
 |url         = http://avalon.law.yale.edu/18th_century/jeffplan.asp
 |title       = Plan for Establishing Uniformity in the Coinage, Weights, and Measures of the United States
 |author      = Thomas Jefferson
 |date        = July 13, 1790
|access-date  = November 8, 2011
 |publisher   = [[United States House of Representatives]]
 |url-status  = live
 |archive-url  = http://archive.wikiwix.com/cache/20110606150632/http://avalon.law.yale.edu/18th_century/jeffplan.asp
 |archive-date = June 6, 2011
|author-link = Thomas Jefferson
}}</ref>

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 {{lang|fr|mesures usuelles}} under Napoleon<ref>{{cite book
|url = https://archive.org/details/allereerstegron00ramagoog
|title = Allereerste Gronden der Cijferkunst
|first = Jacob |last=de Gelder
|location = The Hague and Amsterdam
|language = nl
|year = 1824
|pages = [https://archive.org/details/allereerstegron00ramagoog/page/n364 155]–157
|publisher = De Gebroeders van Cleef
|trans-title = Introduction to Numeracy
|access-date = March 2, 2011
}}</ref> and the newly formed [[German Empire]] adopted the metric system in 1871.<ref>{{cite web
 |url=http://www.csi.tu-darmstadt.de/media/csi/institutes/nearwallreactiveflows/bilderdateien_1/messtechnik/mtmnormen.pdf
 |title=Metrologie 
 |language=de 
 |first=Andreas |last=Dreizler 
 |date=April 20, 2009 |publisher=Technical University of Darmstadt 
 |access-date= March 28, 2011
 |display-authors=etal 
}}{{dead link|date=February 2017|bot=medic}}{{cbignore|bot=medic}}</ref>

The [[Palm (unit)|palm]] (typically 200–280&nbsp;mm) was used in many Mediterranean cities instead of the foot. Horace Doursther, whose reference was published{{clarify|date=July 2013}} 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).{{citation needed|date=October 2022}}

====Obsolete feet details====
In the table below, arbitrary cut-off points of 270&nbsp;mm and 350&nbsp;mm have been chosen.{{citation needed|date=October 2022}}

{| class="wikitable sortable"
|-
! Location
! Modern country
! Local name
! Metric <br />equivalent <br />(mm)
! class="unsortable" | Comments
|-
|[[Vienna]]
|Austria
|{{lang|de|italic=no|Wiener Fuß}}
|316.102<ref name=Bruhns/><ref>[[:File:Fußmaße1.jpg|File]]</ref>{{circular inline|date=February 2024}}
|
|-
|[[Tyrol (state)|Tyrol]]
|Austria
|{{lang|de|italic=no|Fuß}}
|334.12<ref name=DE1842/>
|
|-
|[[Ypres|Ypres (Ieper)]]
|Belgium
|{{lang|nl|italic=no|voet}}
|273.8<ref name=Flanders/>
|
|-
|[[Bruges|Bruges/Brugge]]
|Belgium
|{{lang|nl|italic=no|voet}}
|274.3<ref name=Flanders/>
|
|-
|[[Brussels]]
|Belgium
|{{lang|nl|italic=no|voet}}
|275.75<ref name=Flanders/>
|
|-
|[[Hainaut (province)|Hainaut]]
|Belgium
|{{lang|fr|italic=no|pied}}
|293.39<ref name=Horace/>
|
|-
|[[Liège (province)|Liège]]
|Belgium
|{{lang|fr|italic=no|pied}}
|294.70<ref name=Horace/>
|
|-
|[[Kortrijk]]
|Belgium
|{{lang|nl|italic=no|voet}}
|297.6<ref name=Flanders/>
|
|-
|[[Aalst, Belgium|Aalst]]
|Belgium
|{{lang|nl|italic=no|voet}}
|277.2<ref name="Flanders">{{cite web
|url = http://www.familiekunde-vlaanderen.be/maten-en-gewichten
|title = Maten en gewichten
|language = nl
|trans-title = Weights and measures
|publisher = Vlaamse Vereniging voor Familiekunde (Flemish Association for Family History)
|access-date = October 24, 2011
|year = 2011
|url-status = dead
|archive-url = https://web.archive.org/web/20120425091424/http://www.familiekunde-vlaanderen.be/maten-en-gewichten
|archive-date = April 25, 2012
}}</ref>
|
|-
|[[Mechelen]]
|Belgium
|{{lang|nl|italic=no|voet}}
|278.0<ref name=Flanders/>
|
|-
|[[Leuven]]
|Belgium
|{{lang|nl|italic=no|voet}}
|285.5<ref name=Flanders/>
|
|-
|[[Tournai]]
|Belgium
|{{lang|fr|italic=no|pied}}
|297.77<ref name=Horace/>
|
|-
|[[Antwerp]]
|Belgium
|{{lang|nl|italic=no|voet}}
|286.8<ref name=Flanders/>
|
|-
|[[China]]
|China
|tradesman's foot
|338.3<ref name=rose/>
|
|-
|China
|China
|mathematician's foot
|333.2<ref name=rose/>
|
|-
|China
|China
|builder's foot
|322.8<ref name=rose/>
|
|-
|China
|China
|surveyor's foot
|319.5<ref name=rose/>
|
|-
|[[Moravia]]
|Czech Republic
|{{lang|cs|italic=no|stopa}}
|295.95<ref name=DE1842/>
|
|-
|rowspan="2"|[[Prague]]
|rowspan="2"|Czech Republic
|rowspan="2"|{{lang|cs|italic=no|stopa}}
|296.4<ref name=DE1851V2/>
|(1851) Bohemian foot or shoe
|-
|301.7<ref name=Traite/>
|(1759) Quoted as "11 {{lang|fr|pouces}} {{sfrac|1|3|4}} {{lang|fr|lignes}}"<ref group=Notes name=lignes/>
|-
|rowspan="2"|[[Denmark]]
|rowspan="2"|Denmark
|rowspan="2"|{{lang|da|italic=no|fod}}
|313.85<ref name=Bruhns/>
|Until 1835, thereafter the Prussian foot
|-
|330.5<ref name=Traite/>
|(1759) Quoted as "{{sfrac|2|1|2}} {{lang|fr|lignes}} larger than the {{lang|fr|pied}} [of Paris]"<ref group=Notes name=lignes/>
|-
|[[France]]
|France
|{{lang|fr|italic=no|pied du roi}}
|324.84<ref name="CGCP">{{cite web
 |url         = http://www.cgcp.asso.fr/FAQ/divers/anciennes_unites.php
 |title       = Les anciennes unités et leurs équivalences
 |trans-title = Old units and their equivalences
 |language    = fr
 |publisher   = Le Cybergroupe Généalogique de Charente Poitevine
 |year        = 2011
 |access-date  = February 25, 2011
|url-status     = live
 |archive-url  = https://web.archive.org/web/20110720204605/http://www.cgcp.asso.fr/FAQ/divers/anciennes_unites.php
 |archive-date = July 20, 2011
|df          = mdy-all
}}</ref>
|<ref group=Notes>The original meter was computed using pre-metric French units.</ref>
|-
|[[Angoulême]]
|France
|{{lang|fr|italic=no|pied d'Angoulême}}
|347.008<ref name="Guilhiermoz">{{cite journal
|journal = Bibliothèque de l'École des chartes
|title = De l'équivalence des anciennes mesures. A propos d'une publication récente
|trans-title = Values of ancient measures quoted in recent publications
|language = fr
|year = 1913
|volume= 74
|pages = 267–328
|first = P
|last = Guilhiermoz
|doi=10.3406/bec.1913.448498}}</ref>
|
|-
|[[Bordeaux]] (urban)
|France
|{{lang|fr|italic=no|pied de ville de Bordeaux}}
|343.606<ref name=Guilhiermoz/>
|
|-
|Bordeaux (rural)
|France
|{{lang|fr|italic=no|pied de terre de Bordeaux}}
|357.214<ref name=Guilhiermoz/>
|
|-
|[[Strasbourg]]
|France
|{{lang|fr|italic=no|pied de Strasbourg}}
|294.95<ref name=Guilhiermoz/>
|
|-
|[[Württemberg]]
|Germany
|{{lang|de|italic=no|Fuß}}
|286.49<ref name=DE1842/>
|
|-
|[[Hanover]]
|Germany
|{{lang|de|italic=no|Fuß}}
|292.10<ref name=DE1842/>
|
|-
|[[Augsburg]]
|Germany
|{{lang|de|italic=no|römischer Fuß}}
|296.17<ref name=DE1851/>
|
|-
|[[Nuremberg]]
|Germany
|{{lang|de|italic=no|Fuß}}
|303.75<ref name=DE1851/>
|
|-
|[[Meiningen]]-[[Hildburghausen]]
|Germany
|{{lang|de|italic=no|Fuß}}
|303.95<ref name=DE1842/>
|
|-
|[[Oldenburg (city)|Oldenburg]]
|Germany
|{{lang|de|italic=no|römischer Fuß}}
|296.41<ref name=DE1842/>
|
|-
|[[Weimar]]
|Germany
|{{lang|de|italic=no|Fuß}}
|281.98<ref name=DE1842/>
|
|-
|[[Lübeck]]
|Germany
|{{lang|de|italic=no|Fuß}}
|287.62<ref name=Bruhns/>
|
|-
|[[Aschaffenburg]]
|Germany
|{{lang|de|italic=no|Fuß}}
|287.5<ref name=Horace/>
|
|-
|[[Darmstadt]]
|Germany
|{{lang|de|italic=no|Fuß}}
|287.6<ref name=Horace/>
|Until 1818, thereafter the Hessen "metric foot"
|-
|[[Bremen]]
|Germany
|{{lang|de|italic=no|Fuß}}
|289.35<ref name=Bruhns/>
|
|-
|[[Rhineland]]
|Germany
|{{lang|de|italic=no|Fuß}}
|313.7<ref name=rose/>
|
|-
|[[Berlin]]
|Germany
|{{lang|de|italic=no|Fuß}}
|309.6<ref name=rose/>
|
|-
|[[Hamburg]]
|Germany
|{{lang|de|italic=no|Fuß}}
|286.8<ref name=rose/>
|
|-
|[[Bavaria]]
|Germany
|{{lang|de|italic=no|Fuß}}
|291.86<ref name=DE1842/>
|
|-
|[[Aachen]]
|Germany
|{{lang|de|italic=no|Fuß}}
|282.1<ref name=DE1851/>
|
|-
|[[Leipzig]]
|Germany
|{{lang|de|italic=no|Fuß}}
|282.67<ref name=DE1842/>
|
|-
|[[Dresden]]
|Germany
|{{lang|de|italic=no|Fuß}}
|283.11<ref name=DE1842/>
|
|-
|[[Saxony]]
|Germany
|{{lang|de|italic=no|Fuß}}
|283.19<ref name=Bruhns/>
|
|- id=Prussia
|[[Prussia]]
|Germany, Poland, Russia etc.
|{{lang|de|italic=no|Rheinfuß}}
|313.85<ref name=Bruhns/>
|
|-
|[[Frankfurt am Main]]
|Germany
|{{lang|de|italic=no|Fuß}}
|284.61<ref name=DE1842/>
|
|-
|[[Venice]] & [[Lombardy]]
|Italy
|
|347.73<ref name=DE1842/>
|
|-
|[[Turin]]
|Italy
|
|323.1<ref name=rose/>
|
|-
|[[Rome]]
|Italy
|{{lang|it|italic=no|piede romano}}
|297.896<ref name=Guilhiermoz/>
|
|-
|[[Riga]]
|Latvia
|{{lang|lv|italic=no|pēda}}
|274.1<ref name=rose/>
|
|-
|[[Malta]]
|Malta
|{{lang|fr<!--assumed: possibly Maltese-->|italic=no|pied}}
|283.7<ref name=rose/>
|
|-
|[[Utrecht]]
|Netherlands
|{{lang|nl|italic=no|voet}}
|272.8<ref name="rose">{{cite book
 | last =Rose
 | first =Joshua
 | title =Pattern Makers Assistant
 | publisher =D. van Nostrand Co.
 | edition =9th
 | year =1900
 | location =New York
 | pages =264
 }}</ref>
|
|-
|[[Amsterdam]]
|Netherlands
|{{lang|nl|italic=no|voet}}
|283.133<ref name=NL2/>
|Divided into 11 {{lang|nl|duimen}} (inches, {{literally|thumbs}})
|-
|{{ill|Honsbossche en Rijpse|nl|Hondsbossche Zeewering}}
|Netherlands
|{{lang|nl|italic=no|voet}}
|285.0<ref name=NL2/>
|
|-
|[['s-Hertogenbosch]]
|Netherlands
|{{lang|nl|italic=no|voet}}
|287.0<ref name=NL2/>
|
|-
|[[Gelderland]]
|Netherlands
|{{lang|nl|italic=no|voet}}
|292.0<ref name=NL2/>
|
|-
|[[:nl: Bloois|Bloois (Zeeland)]]
|Netherlands
|{{lang|nl|italic=no|voet}}
|301.0<ref name=NL2/>
|
|-
|[[:nl:Wyldemerk|Schouw]]
|Netherlands
|{{lang|nl|italic=no|voet}}
|311.0<ref name=NL2/>
|
|-
|[[Rotterdam]]
|Netherlands
|{{lang|nl|italic=no|voet}}
|312.43<ref name=Horace/>
|
|-
|[[Rijnland]]
|Netherlands
|{{lang|nl|italic=no|voet}}
|314.858<ref name=NL2/>
|
|-
|[[Norway]]
|Norway
|{{lang|no|italic=no|fot}}
|313.75<ref>{{cite news
|title = Mål, vekt og norsk selvstendighet
|language=no
|trans-title = Dimensions, weight and Norwegian independence
|newspaper = Aftenposten
|date = July 21, 2005
|first = leif
|last = halbo
}}</ref>
|(1824–1835)<ref group="Notes">The Norwegian {{lang|no|fot}} was defined in 1824 as the length of a (theoretical) pendulum that would have a period of {{sfrac|12|38}}&nbsp;seconds at 45° from the equator.</ref> Thereafter as for Sweden.
|-
|rowspan="2"|[[Warsaw]]
|rowspan="2"|Poland
|rowspan="2"|{{lang|pl|italic=no|stopa}}
|297.8<ref name="PolishLocal">{{Citation needed|date=October 2011}} – Information copied from [[:pl:Stopa polska]]</ref>
|Until 1819
|-
|288.0<ref name=Horace/>
|(From 1819) Polish {{lang|pl|italic=no|stopa}}
|-
|[[Lisbon]]
|Portugal
|{{lang|pt|italic=no|pé}}
|330.0<ref name=DE1851/>
|(From 1835)<ref group=Notes>Prior to 1835, the {{lang|pt|pé}} or foot was not used in Portugal; instead a palm was used. In 1835 the size of the palm was increased from 217.37&nbsp;mm (according to Palaiseau) to 220&nbsp;mm.</ref>
|-
|[[South Africa]]
|South Africa
|[[Cape foot]]
|314.858<ref>{{cite web
 |url         = http://www.fig.net/pub/cairo/papers/wshs_03/wshs03_02_zakiewich.pdf
 |author      = Tomasz Zakiewicz
 |title       = The Cape Geodetic Standards and Their Impact on Africa
 |publisher   = FIG
 |location    = Cairo
 |date        = April 2005
 |access-date  = January 4, 2012
|url-status  = live
 |archive-url  = https://web.archive.org/web/20120120235610/http://www.fig.net/pub/cairo/papers/wshs_03/wshs03_02_zakiewich.pdf
 |archive-date = January 20, 2012
|df          = mdy-all
}}</ref>
|Originally equal to the Rijnland foot; redefined as 1.033 English feet in 1859.
|-
|[[Burgos]] and [[Castile (historical region)|Castile]]
|Spain
|{{lang|es|italic=no|pie de Burgos/<br />Castellano}}
|278.6<ref name=Traite/>
|(1759) Quoted as "122.43 {{lang|fr|lignes}}"<ref group=Notes name=lignes/>
|-
|[[Toledo, Spain|Toledo]]
|Spain
|{{lang|es|italic=no|pie}}
|279.0<ref name=Traite/>
|(1759) Quoted as "10 {{lang|fr|pouces}} 3.7 {{lang|fr|lignes}}"<ref group=Notes name=lignes>The source document used pre-metric French units ({{lang|fr|pied}}, {{lang|fr|pouce}} and {{lang|fr|ligne}}).</ref>
|-
|[[Sweden]]
|Sweden
|{{lang|sv|italic=no|fot}}
|296.9<ref name=Bruhns/>
|= 12 {{lang|sv|tum}} (inches). The Swedish {{lang|sv|fot}} was also used in Finland ({{lang|fi|jalka}}).
|-
|[[Zürich]]
|Switzerland
|
|300.0<ref name=rose/>
|
|-
|[[Galicia (eastern Europe)|Galicia]]
|Ukraine, Poland
|{{lang|pl|italic=no|stopa galicyjska}}
|296.96<ref name=Horace/>
|Part of Austria–Hungary before World War I
|-
|[[Scotland]]
|United Kingdom
|<!--Scots/Gaelic spellings not attested in source: fuit, fit, troigh-->
|305.287<ref>{{cite web
 |url         = http://www.scan.org.uk/measures/distance.asp
 |title       = Scottish Weights and Measures: Distance and Area
 |publisher   = Scottish Archive Network
 |access-date  = January 28, 2010
|url-status  = live
 |archive-url  = https://web.archive.org/web/20090814193601/http://www.scan.org.uk/measures/distance.asp
 |archive-date = August 14, 2009
|df          = mdy-all
}}</ref>
|<ref group=Notes>The Scots foot ceased to be legal after the [[Acts of Union 1707|Act of Union]] in 1707.</ref>
|}

In Belgium, the words {{lang|fr|pied}} (French) and {{lang|nl|voet}} (Dutch) would have been used interchangeably.{{citation needed|date=October 2022}}

====Notes====
<references group=Notes/>

==Present day uses==

===International ISO-standard and other intermodal shipping containers ===
[[International Standards Organisation]] (ISO)-defined [[intermodal containers]] 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. <br>
Quantities of global shipping containers are still primarily counted in [[Twenty-foot Equivalent Unit]]s, or TEUs.

===Aviation===
Everyday global (civilian) air traffic / aviation continues to be controlled in [[flight level]]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).

===Relation to shoe size===
The length of the (international) foot corresponds to a human foot with [[shoe size]] of 13 (UK), 14 (US male), 15.5 (US female) or 48 (EU sizing).<ref>{{cite web |title=Why are shoe sizes as they are?  |last=Melissa |url=https://www.todayifoundout.com/index.php/2016/03/pedestrian-origins-modern-shoe-sizes/ |website=Today I found out |date=30 March 2016}} (12×3=36. US(m): 36−22=14, UK: 36−23=13, EU:30.5×1.5=45.75 then +2 "for comfort" plus rounding = 48)</ref>{{better source|reason=todayifoundout.com is identified as "not generally reliable"|date=November 2023}}

==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]] in ''[[square foot]]''.<ref>{{Cite web |url=http://www.unc.edu/~rowlett/units/dictL.html |title=Units: L |access-date=September 20, 2021 |archive-date=July 2, 2016 |archive-url=https://web.archive.org/web/20160702030033/http://www.unc.edu/~rowlett/units/dictL.html |url-status=dead }}</ref>

==See also==
* [[Anthropic units]]
* [[History of measurement]]
* [[International System of Units]]
* [[Korean units of measurement]]
* [[N. David Mermin#Word and phrase coinages|Mermin's foot]]
* [[Pous]]
* [[Systems of measurement]]

== Notes ==
<references group = "Note" />

==References==
{{Reflist}}

{{Imperial units}}
{{United States Customary Units}}
{{Authority control}}

{{DEFAULTSORT:Foot}}
[[Category:Customary units of measurement in the United States]]
[[Category:Human-based units of measurement]]
[[Category:Imperial units]]
[[Category:Units of length]]