Hectare

Hectare
Illustration of One Hectare.png
Visualization of one hectare
Unit information
Unit systemNon-SI unit accepted for use with SI
Unit ofArea
Symbolha 
In SI base units:1 ha = 104 m2

The hectare (ɑːr/; SI symbol: ha) is an SI accepted metric system unit of area equal to a square with 100 metre sides, or 10,000 m2, and is primarily used in the measurement of land.[1] There are 100 hectares in one square kilometre. An acre is about 0.405 hectare and one hectare contains about 2.47 acres.

In 1795, when the metric system was introduced, the "are" was defined as 100 square metres and the hectare ("hecto-" + "are") was thus 100 "ares" or ​1100 km2. When the metric system was further rationalised in 1960, resulting in the International System of Units (SI), the are was not included as a recognised unit. The hectare, however, remains as a non-SI unit accepted for use with the SI units, mentioned in Section 4.1 of the SI Brochure as a unit whose use is "expected to continue indefinitely".[1]

The name was coined in French, from the Latin ārea.[2]

Comparison of area units
UnitSI
1 ca1 m2
1 a100 m2
1 ha10,000 m2
100 ha1,000,000 m2
1 km2
non-SI comparisons
non-SImetric
0.3861 sq mi1 km2
2.471 acre1 ha
107,639 sq ft1 ha
1 sq mi259.0 ha
1 acre0.4047 ha

History

The metric system of measurement was first given a legal basis in 1795 by the French Revolutionary government. The law of 18 Germinal, Year III (7 April 1795) defined five units of measure:[3]

  • The metre for length
  • The are (100 m2) for area [of land]
  • The stère (1 m3) for volume of stacked firewood[4]
  • The litre (1 dm3) for volumes of liquid
  • The gram for mass

In 1960, when the metric system was updated as the International System of Units (SI), the are did not receive international recognition. The International Committee for Weights and Measures (CIPM) makes no mention of the are in the current (2006) definition of the SI, but classifies the hectare as a "Non-SI unit accepted for use with the International System of Units"[5]

In 1972, the European Economic Community (EEC) passed directive 71/354/EEC,[6] 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 the are (and implicitly the hectare) whose use was limited to the measurement of land.

Many UK farmers, especially older ones, still use the acre for everyday calculations, and convert to hectares only for official (especially European Union) paperwork. Farm fields can have very long histories which are resistant to change, with names such as "the six acre field" stretching back hundreds of years and across generations of family farmers. Some younger agricultural workers are now beginning to think in hectares as their "first language", though this is more typical of professional consultants and managers than of traditional farming and land-owning families, and in some circles may be viewed as a social class indicator.

Other Languages
Afrikaans: Hektaar
Alemannisch: Hektar
አማርኛ: ሄክታር
العربية: هكتار
aragonés: Hectaria
asturianu: Hectárea
Avañe'ẽ: Hectárea
azərbaycanca: Hektar
বাংলা: হেক্টর
беларуская: Гектар
беларуская (тарашкевіца)‎: Гектар
български: Хектар
Boarisch: Hektar
བོད་ཡིག: ཧེག་ཐ།
bosanski: Hektar
brezhoneg: Hektar
català: Hectàrea
čeština: Hektar
Cymraeg: Hectr
dansk: Hektar
Deutsch: Hektar
dolnoserbski: Hektar
eesti: Hektar
Ελληνικά: Εκτάριο
español: Hectárea
Esperanto: Hektaro
euskara: Hektarea
فارسی: هکتار
føroyskt: Hektari
français: Hectare
Frysk: Hektare
furlan: Etar
Gaeilge: Heicteár
Gàidhlig: Heactair
galego: Hectárea
ગુજરાતી: હેક્ટર
客家語/Hak-kâ-ngî: Kûng-khín
한국어: 헥타르
Հայերեն: Հեկտար
hornjoserbsce: Hektar
hrvatski: Hektar
Bahasa Indonesia: Hektare
Ирон: Гектар
íslenska: Hektari
italiano: Ettaro
עברית: הקטאר
ქართული: ჰექტარი
қазақша: Гектар
Kiswahili: Hektari
Кыргызча: Гектар
Latina: Hectarium
latviešu: Hektārs
lietuvių: Hektaras
Limburgs: Hektaar
magyar: Hektár
македонски: Хектар
മലയാളം: ഹെക്ടേർ
मराठी: हेक्टर
مصرى: هكتار
Bahasa Melayu: Hektar
Nederlands: Hectare
Nedersaksies: Bunder
日本語: ヘクタール
norsk: Hektar
norsk nynorsk: Hektar
occitan: Ectara
oʻzbekcha/ўзбекча: Gektar
ਪੰਜਾਬੀ: ਹੈਕਟੇਅਰ
Pälzisch: Hektar
پنجابی: ہیکٹر
Plattdüütsch: Hektar
polski: Hektar
português: Hectare
română: Hectar
русский: Гектар
саха тыла: Гектаар
shqip: Hektari
Simple English: Hectare
slovenčina: Hektár
slovenščina: Hektar
Soomaaliga: Hektar
српски / srpski: Хектар
srpskohrvatski / српскохрватски: Hektar
suomi: Hehtaari
svenska: Hektar
Tagalog: Ektarya
தமிழ்: எக்டேர்
తెలుగు: హెక్టారు
Türkçe: Hektar
тыва дыл: Га
українська: Гектар
ئۇيغۇرچە / Uyghurche: گېكتار
vèneto: Ètaro
vepsän kel’: Gektar
Tiếng Việt: Hecta
文言: 公頃
West-Vlams: Hectoare
Winaray: Hektarya
粵語: 公頃
Zeêuws: Hectare
žemaitėška: Hektars
中文: 公顷