Stone (unit)

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German medieval scale for weighting bales of wool. The unit of measure was the local stone.

The stone (abbreviation st[1]) is an informal unit of measure used in Great Britain and Ireland for measuring human body weight. The stone was formerly used for purposes of trade in many European countries where its value ranged from about 3 to 15 kg, but with the advent of metrication from the mid-nineteenth century onwards it was superseded by the kilogram; its use for trade in the United Kingdom and in Ireland being rescinded in the 1980's. It may be unfamiliar to an international audience.



Roman stone weight of 40 librae (~13 kg), c 200 AD, on display in Eschborn Museum, Germany.

The name "stone" derives from the use of stones for weights - a practice that dates back into antiquity. The ancient Hebrew Law against the carrying of "diverse weights, a large and a small"[2] is more literally translated as "you shall not carry a stone and a stone (אבן ואבן), a large and a small". There was no "standard" stone in the ancient Jewish world,[3] but in Roman times weights crafted to a multiple of the Roman libra (a pound of about 327.54 g) for use in commerce were often made of stone.[4] Such weights varied in quality - 10 and 50 [Roman] pound examples acquired in Italy, possibly from Pompeii, were of polished blackstone,[5] while a 40 pound example on exhibition in Eschborn, close to the Roman frontier in Germany, was made of sandstone.[6]

Great Britain and Ireland

During the Middle Ages, a conveniently-sized rock was often chosen as a local standard for weighing agricultural commodities, but the weight of such rocks varied with the commodity and region. By the late Middle Ages, international trade such as England's exports of raw wool to Florence required a fixed standard, and in 1389 a royal statute of Edward III fixed the stone of wool at 14 pounds.[7]

In England potatoes were traditionally sold in stone and half-stone (14 pounds and 7 pounds, respectively) increments, but the Oxford English Dictionary contains examples including the following:[8]

CommodityNumber of Pounds
Wool14, 15, 24
Sugar and spice8
Beef and mutton8

The 1772 edition of the Encyclopædia Britannica defined the stone as follows.[9]

STONE also denotes a certain quantity or weight of some commodities. A stone of beef, in London, is the quantity of eight pounds; in Hertfordshire, twelve pounds; in Scotland sixteen pounds.

In 1661 the Royal Commission of Scotland recommended that the Troy stone be used as a standard of weight and that it be kept in the custody of the burgh of Lanark. The Scots stone was equal to 16 Scots pounds (17 lb 8 oz avoidupois or 7.936 kg). The tron (or local) stone of Edinburgh, also standardised in 1661, was 16 tron pounds (24 lb 1 oz avoidupois or 9.996 kg)[10][11] In 1789 an encyclopedic enumeration of measurements was printed for the use of "his Majesty's Sheriffs and Stewards Depute, and Justices of Peace, ... and to the Magistrates of the Royal Boroughs of Scotland" and provided a county-by-county and commodity-by-commodity breakdown of values and conversions for the stone and other measures.[12] The Scots stone ceased to be used for trade when the Act of 1824 established a uniform system of measure across the whole of the United Kingdom, which at that time included all of Ireland.[13]

Ireland used the pound avoidupois: before the early nineteenth century, as in England, the stone varied both with locality and with commodity (e.g., the Belfast stone for measuring flax equaled 16.75 pounds[14])with the most usual value being 14 pounds.[15] Among the oddities related to the use of the stone was the practice in Clare of a stone of potatoes being 16 lbs in the summer and 18 lbs in the winter.[15]

The Weights and Measures Act of 1824 (which applied to all of the United Kingdom) consolidated the weights and measures legislation of several centuries into a single document. It revoked the provision that bales of wool should be made up of 20 stones, each of 14 pounds, but made no provision for the continued use of the stone. Ten years later, a stone still varied from 5 pounds (glass) to 8 pounds (meat and fish) to 14 pounds (wool and "horseman's weight").[16] However, the Act of 1835 permitted a stone of 14 pounds to be used for trade[17] but other values continued to be used - Britten, in 1880 for example, catalogued a number of different values of the stone in various British towns and cities ranging from 4 lbs to 26 lbs[18] A stone of 8 lbs continued to be used for meat at Smithfield until shortly before the second world war.[19]

In 1965, the then Federation of British Industry informed the British Government that its members favoured the adoption of the metric system. The Board of Trade, on behalf of the Government, agreed to support to a ten-year metrication program. There would be minimal legislation, as the program was to be voluntary and costs were to be borne where they fell.[20] Under the guidance of the Metrication Board, the agricultural product markets achieved a voluntary switchover by 1976.[21] With the adoption of metric units by the agricultural sector, the stone was in practice no longer used for trade, and in the Weights and Measures Act 1985, passed in compliance with EU directive 80/181/EEC",[22] the stone was removed from the list of units permitted for trade in the United Kingdom.[23] In 1983, in response to the same directive, similar legislation was passed in Ireland.[24]

Continental Europe

Before the advent of metrication, units called "stone" (German: Stein; Dutch: steen) were used in many North European countries.[25] Its value, usually between 3 and 10 kg, varied from city to city and sometimes from commodity to commodity. The number of local "pounds" in a stone also varied from city to city. During the early 19th century, states such as the Netherlands (including Belgium) and the South Western German states which had redefined their system of measures using the kilogramme des Archives as a reference for weight (mass) also redefined their stone to align it with the kilogram.

This table shows a selection of stones from various North European Continental cities:

CityModern CountryDescriptionWeight of
stone in
Weight of
stone in
local pounds
Dresden[26]Germanystein10.1522Before 1841
10.020From 1841 onwards
Germanyschwerer Stein10.29622heavy stone
leichter Stein5.14811light stone
Danzig (Gdańsk)[26]
Königsberg (Kaliningrad)[26]
grosser Stein15.44433large stone
kleiner Stein10.29622small stone
Bremen[26]GermanySteinflachs9.9720stone of flax
Stein Wolle und Federn4.98510stone of wool and feathers
Oldenburg[26]GermanyStein Flachs9.69220stone of flax
Steinwolle und Federn4.84610stone of wool and feathers
Amsterdam[26]NetherlandsSteen3.9538Before 1817
33"Metric stone" (after 1817)
Breslau (Wrocław)[26]PolandStein9.73224
Prague[27]Czech RepublicStein10.2920
Stockholm[27]SwedenSten13.6032(32 Skålpund)
Warsaw[27]PolandKamieni10.142525 Funtów
Vilnius[27]LithuaniaKamieni14.9924040 Funtów

Current use

While the stone is a very common unit of weight in the British Isles, it is virtually unknown even as a historical unit in North America and other places; use of the term can mystify an international audience.

The stone was not included in the Directive 80/181/EEC as a unit of measure that could be used within the EEC for "economic, public health, public safety or administrative purposes",[22] though its use as a "supplementary unit" was permitted. The scope of the directive was extended to include all aspects of the EU internal market as from 1 January 2010.[22]

The 1985 Weights and Measures Act aligned British law with the EU directive. The Act repealed earlier acts that defined the stone as a unit of measure for trade.[23] (British law had previously been silent regarding other uses of the stone.) However the stone remains widely used in Britain and Ireland for human body weight: in those countries people may commonly be said to weigh, e.g., "11 stone 4" (11 stones and 4 pounds), rather than "72 kilograms" as in many other countries, or "158 pounds" (the conventional way of expressing the same weight in the United States and Canada). The correct plural form of stone in this context is stone (as in, "11 stone" or "12 stone 6 pounds"); in other contexts, the correct plural is stones (as in, "Please enter your weight in stones and pounds").

In many sports in both the UK and in Ireland such as professional boxing, wrestling and horse racing[28] the stone is used to express weight; in most other countries kilograms are used exclusively. However in July 2012 it was announced that at three of London's main race courses metric units would be trialled alongside imperial units.[29] In the Olympic Games kilograms are used to define the weight divisions in Greco-Roman wrestling, freestyle wrestling, boxing and judo[30].


In current common usage, one stone is equivalent to approximately 6.35 kg (6.35029318 kg precisely) and to 14 pounds. A conversion table can be found here.

See also



  1. ^ 'Concise Oxford Dictionary', Oxford University Pres; 1964
  2. ^ Deuteronomy 25:13
  3. ^ The Pictorial Bible; being the Old and New Testaments according to the Authorised Version ... to which are added Original Notes. London: Charles Knight & Co. 1836. Retrieved 14 March 2012. 
  4. ^ de Montfaucon, Bernard; Humphreys, David (Translator) (1722). Antiquity explained, and represented in sculptures, Volumes 3-4. London. pp. 107–109. 
  5. ^ for example, <be>Kisch, Bruno (1956). "Two Remarkable Roman Stone Weights in the Edward C. Streeter Collection at the Yale Medical Library". Journal of the History of Medicine and Allied Sciences XI (1): 97–100. 
  6. ^ A Roman stone weight of 40 librae is on exhibition in the Eschborn town museum (Germany) - viewed on 12 March 2012
  7. ^ Encyclopædia Britannica,, retrieved 14 March 2012 
  8. ^ Oxford English Dictionary definition for Stone - meaning 14a
  9. ^ Encyclopædia Britannica Vol III, Edinburgh - 1772.
  10. ^ "Scottish Weights and Measures: Weight". SCAN Weights and Measures Guide: Background information about Scottish weights and measures. Scottish Archive Network. Retrieved 2011-11-08. 
  11. ^ "Scottish Weights and Measures: Background". SCAN Weights and Measures Guide: Background information about Scottish weights and measures. Scottish Archive Network. Retrieved 2011-11-08. 
  12. ^ A Proposal for Uniformity of Weights and Measures in Scotland by Execution of Laws Now in Force. Edinburgh: Peter Hill. 1789. 
  13. ^ Mairi Robinson, ed. (2005) [1985]. "Appendix - Scottish Currency, Weights and Measures". Concise Scots Dictionary. Edinburgh: Edinburgh University Press Ltd. p. 817. ISBN 1-902930-00-2. 
  14. ^ Chaney, Henry J. (1897). Our Weights and Measures. London: Eyre and Spottiswoode. pp. 24. 
  15. ^ a b Edward Wakefield (1812). An account of Ireland, statistical and political. II. London: Longman, Husrts, Rees, Orme and Brown. pp. 197–202al. 
  16. ^ Gregory, Olinthus (1834). Mathematics for Practical Men. Philedelphia: E. L. Carey and A. Hart. pp. 21. 
  17. ^ Poppy, TG (4 June 1957). "The Development of Weights and Measures Control in the United Kingdom". Report of the National Conference on Weights and Measures, Volumes 41-45. Forty-second National Conference on Weights and Measures. Washingtion DC: US Department of Commerce - National Institute of Standards (NIST). pp. 22-34. 
  18. ^ Zupko, Ronald Edward (1985). A Dictionary of Weights and Measures for the British Isles. American Philosophical Society. pp. 391–398. 
  19. ^ United Kingdom, Parliamentary Debates, House of Lords, 1 March 1938, columns 901–902.
  20. ^ White Paper on Metrication (1972) – Summary and Conclusions. London: Department of Trade and Industry Consumer and Competition Policy Directorate. para 42 - 455. 
  21. ^ Final Report of the Metrication Board (1980). London: Department of Trade and Industry Consumer and Competition Policy Directorate. Appendix A. 
  22. ^ a b c The Council of the European Communities (1979-12-21). "Council Directive 80/181/EEC of 20 December 1979 on the approximation of the laws of the Member States relating to Unit of measurement and on the repeal of Directive 71/354/EEC". Retrieved 2009-02-07. 
  23. ^ a b UK Parliament. Weights and Measures Act 1985 as amended (see also enacted form), from
  24. ^ "S.I. No. 235/1983 — European Communities (Units of Measurement) Regulations, 1983.". Office of the Attorney General. Retrieved 28 June 2012. 
  25. ^ Doursther, Horace (1840). Dictionnaire universel des poids et mesures anciens et modernes. Bruxelles: M. Hayez. p. 424. Retrieved 25 October 2011. 
  26. ^ a b c d e f g h i j k l m n o Noback, Christian; Noback, Friedrich Eduard (1851) (in German). Vollständiges tasehenbuch der Münz-, Maass- und Gewichts-Verhältnisse etc. aller Länder und Handelsplätze [Comprehensive pocketbook of money, weights and measures for all counties and trading centres]. I. Leipzig: F. А. Вrockhaus. Retrieved 24 October 2011. 
  27. ^ a b c d e f Noback, Christian; Noback, Friedrich Eduard (1851) (in German). Vollständiges tasehenbuch der Münz-, Maass- und Gewichts-Verhältnisse etc. aller Länder und Handelsplätze [Comprehensive pocketbook of money, weights and measures for all counties and trading centres]. II. Leipzig: F. А. Вrockhaus. Retrieved 24 October 2011. 
  28. ^ HRI Directives. Ballymany, Curragh, Co Kildare: Horse Racing, Ireland. Retrieved 21 July 2012. 
  29. ^ Lysaght, Cornelius (25 July 2012). "Sandown goes metric as metres are tested alongside furlongs". BBC Sport. Retrieved 25 July 2012. 
  30. ^ The Sport. Loughborough: British Judo Association. Retrieved 21 July 2012. 

External links