Image comparing the hectare (the small blue area at lower left) to other units. The entire yellow square is onesquare mile.
Thehectare (/ˈhɛktɛər,-tɑːr/;SI symbol:ha) is anon-SImetric unit ofarea equal to a square with 100-metre sides (1 hm2), that is, 10,000 square metres (10,000 m2), and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. Anacre is about 0.405 hectares and thus one hectare is about 2.47 acres.
St. Enda's GAA ground, inOmagh. The playing field used inGaelic football andhurling is a little over a hectare in size.
In 1795, when the metric system was introduced, theare was defined as 100square metres, or one squaredecametre, and the hectare ("hecto-" + "are") was thus 100ares or1/100 km2 (10000 square metres). When the metric system was further rationalised in 1960, resulting in theInternational System of Units (SI), theare was not included as a recognised unit. The hectare, however, remains as a non-SI unit accepted for use with the SI and whose use is "expected to continue indefinitely". Though the dekare/decaredaa (1000 m2) andare (100 m2) are not officially "accepted for use", they are still used in some contexts.
The hectare (/ˈhɛktɛər,-tɑːr/[2]), although not a unit of SI, is the only named unit of area that isaccepted for use with SI units.[3] The name was coined in French, from the Latinārea.[4] In practice the hectare is fully derived from the SI, being equivalent to a square hectometre. It is widely used throughout the world for the measurement of large areas of land,[5] and it is the legal unit of measure in domains concerned with land ownership, planning, andmanagement, including law (land deeds), agriculture,forestry, andtown planning throughout theEuropean Union,[6]South Africa,New Zealand,Australia, Canada and the United Kingdom.However, the United States and Myanmar (Burma)[7][8] use theacre instead of the hectare for measuring surface or land area.
In many countries, metrification redefined or clarified existing measures in terms of metric units. The following legacy units of area have been redefined as being equal to one hectare:[9]
In Mexico, land area measurements are commonly given as combinations of hectares, ares, and centiares.[13] These are commonly written separated by ahyphen; for example,1-21-00.26 ha would mean 1 hectare, 21 are, and 0.26 centiare (12100.26 m2).
The metric system of measurement was first given a legal basis in 1795 by theFrench Revolutionary government. The law of18 Germinal, Year III (7 April 1795) defined five units of measure:[14]
In 1960, when the metric system was updated as the International System of Units (SI), theare did not receive international recognition. TheInternational Committee for Weights and Measures (CIPM) makes no mention of theare in the 2019 edition of the SI brochure, but classifies the hectare as a "Non-SI unit accepted for use with the International System of Units".[16]
In 1972, theEuropean Economic Community (EEC) passed directive 71/354/EEC,[17] which catalogued the units of measure that might be used within the Community. The units that were catalogued replicated the recommendations of the CGPM, supplemented by a few other units including theare (and implicitly thehectare) whose use was limited to the measurement of land.
Thedecimilliare (dma, sometimes seen incadastre area evaluation of real estate plots) is1/10,000 are or one square decimetre.[18] Such usage of adouble prefix is non-standard. The decimilliare is (100 mm)2 or roughly a four-inch-by-four-inch square. (The decimilliare is smaller by approximately 3.1%.)
"Are (unit)" redirects here. For the English verb, seeTo Be.
Theare (/ɑːr/[22] or/ɛər/[23]) is a unit of area, equal to 100 square metres (10 m × 10 m), used for measuring land area. It was defined by older forms of themetric system, but is now outside the modernInternational System of Units (SI).[24] It is still commonly used in speech to measure real estate, in particular in Indonesia, India, and in various European countries.
InRussian and some other languages of the formerSoviet Union, theare is calledsotka (сотка: 'a hundred', i.e. 100 m2 or1/100 hectare). It is used to describe the size of suburbandacha orallotment garden plots or small city parks where the hectare would be too large. Many Russian dachas are 6 ares in size (in Russian,шесть соток).
Thedecare ordekare (/ˈdɛkɑːr,-ɛər/) is derived fromdeca andare, and is equal to 10 ares or 1000 square metres. It is used inNorway[25] and in the formerOttoman areas of theMiddle East andBulgaria[26] as a measure of land area. The names of the older land measures of similar size are usually used, redefined as exactly one decare:
TheUnicode characterU+33CA㏊SQUARE HA, in theCJK Compatibility block, is intended for compatibility with pre-existing East Asian character codes.[32] It is not intended for use in alphabetic contexts.U+3336㌶SQUARE HEKUTAARU is a combination ofヘクタール (hekutāru), the Japanese translation of "hectare".
^Caillard, Vincent Henry Penalver;Gibb, Elias John Wilkinson (1911)."Turkey" . InChisholm, Hugh (ed.).Encyclopædia Britannica. Vol. 27 (11th ed.). Cambridge University Press. pp. 426–467, see page 442 second para.Two categories of rent, fixed and proportional, are payable to the state by mine-owners. The fixed rent is 10 piastres perjerib (about10000 square metres), to be paid whether the mine is worked or not.
^Oscar van Vlijmen (11 September 2006)."Oppervlakte" [Area].Eenheden, constanten en conversies [Units, constants and conversion] (in Dutch). Archived fromthe original on 19 June 2021. Retrieved15 January 2011.
^Jacob de Gelder (1824).Allereerste Gronden der Cijferkunst [Introduction to Numeracy] (in Dutch). 's-Gravenhage and Amsterdam: de Gebroeders van Cleef. p. 156. Retrieved19 September 2012.
^Thierry Thomasset."Le stère"(PDF).Tout sur les unités de mesure [All the units of measure] (in French). Université de Technologie de Compiègne. Archived fromthe original(PDF) on 21 July 2011. Retrieved21 March 2011.
