The hectare (/ˈhɛktɛər, -tɑːr/; 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. 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 1⁄100 km2 (10,000 square metres). When the metric system was further rationalised in 1960, resulting in the International System of Units ( ), 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".
The name was coined in French, from the Latin ārea.
|1 ca||1 m2|
|1 a||100 m2|
|1 ha||10,000 m2|
|100 ha||1,000,000 m2|
|0.3861 sq mi||1 km2|
|2.471 acre||1 ha|
|107,639 sq ft||1 ha|
|1 sq mi||259.0 ha|
|1 acre||0.4047 ha|
Visualization of one hectare
|Unit system||Non-SI unit accepted for use with SI|
|In SI base units:||1 ha = 104 m2|
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 ( ) 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".
In 1972, the European Economic Community (EEC) passed directive 71/354/EEC, 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.
The names centiare, deciare, decare and hectare are derived by adding the standard metric prefixes to the original base unit of area, the are.
The centiare is one square metre.
The deciare is ten square metres.
The are (/ɑːr/ or /ɛər/) 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 the metric system, but is now outside the modern International System of Units (SI). It is still commonly used in colloquial speech to measure real estate, in particular in Indonesia, India, and in various European countries.
In Russian and other languages of the former Soviet Union, the are is called sotka (Russian: сотка: 'a hundred', i.e. 100 m2 or 1⁄100 hectare). It is used to describe the size of suburban dacha or allotment garden plots or small city parks where the hectare would be too large.
The decare (/ˈdɛkɑːr, -ɛər/) is derived from deca and are, and is equal to 10 ares or 1000 square metres. It is used in Norway and in the former Ottoman areas of the Middle East and the Balkans (Bulgaria) as a measure of land area. Instead of the name "decare", the names of traditional land measures are usually used, redefined as one decare:
The hectare (/ˈhɛktɛər, -tɑːr/), although not a unit of SI, is the only named unit of area that is accepted for use within the SI. 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, and it is the legal unit of measure in domains concerned with land ownership, planning, and management, including law (land deeds), agriculture, forestry, and town planning throughout the European Union. The United Kingdom, United States, Burma, and to some extent Canada use the acre instead.
Some countries that underwent a general conversion from traditional measurements to metric measurements (e.g. Canada) required a resurvey when units of measure in legal descriptions relating to land were converted to metric units. Others, such as South Africa, published conversion factors which were to be used particularly "when preparing consolidation diagrams by compilation".
In many countries, metrication 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:
|Metric and imperial/US customary comparisons|
|Unit||Symbol||Metric equivalents||Imperial/US customary equivalents|
|centiare||ca||1 m2||0.01 a||1.19599 sq yd|
|are||a||100 ca||100 m2||0.01 ha||3.95369 perches|
|decare||daa||10 a||1,000 m2||0.1 ha||0.98842 roods|
|hectare||ha||100 a||10,000 m2||0.01 km2||about 2.4710538 acres|
|square kilometre||km2||100 ha||1,000,000 m2||0.38610 sq mi|
The most commonly used units are in bold.
One hectare is also equivalent to:
The acre is a unit of land area used in the imperial and US customary systems. It is traditionally defined as the area of one chain by one furlong (66 by 660 feet), which is exactly equal to 10 square chains, 1⁄640 of a square mile, or 43,560 square feet, and approximately 4,047 m2, or about 40% of a hectare. Based upon the International yard and pound agreement of 1959, an acre may be declared as exactly 4,046.8564224 square metres.
The acre is a statute measure in the United States and was formerly one in the United Kingdom and almost all countries of the former British Empire, although informal use continues.
In the United States both the international acre and the US survey acre are in use, but they differ by only two parts per million: see below. The most common use of the acre is to measure tracts of land.
Traditionally, in the Middle Ages, an acre was defined as the area of land that could be ploughed in one day by a yoke of oxen.Agriculture in India
The history of Agriculture in India dates back to Indus Valley Civilization Era and even before that in some parts of Southern India. India ranks second worldwide in farm outputs. As per 2018, Agriculture employed 50% of the Indian work force and contributed 17-18% to country's GDP.In 2016. Agriculture and allied sectors like animal husbandry, forestry and fisheries accounted for 15.4% of the GDP (gross domestic product) with about 31% of the workforce in 2014. India ranks first globally with highest net cropped area followed by US and China. The economic contribution of agriculture to India's GDP is steadily declining with the country's broad-based economic growth. Still, agriculture is demographically the broadest economic sector and plays a significant role in the overall socio-economic fabric of India.
India exported $38 billion worth of agricultural products in 2013, making it the seventh largest agricultural exporter worldwide and the sixth largest net exporter. Most of its agriculture exports serve developing and least developed nations. Indian agricultural/horticultural and processed foods are exported to more than 120 countries, primarily in the Middle East, Southeast Asia, SAARC countries, the European Union and the United States.Agriculture in Jordan
Agriculture in Jordan contributed substantially to the economy at the time of Jordan's independence, but it subsequently suffered a decades-long steady decline. In the early 1950s, agriculture constituted almost 40 percent of GNP; on the eve of the June 1967 War, it was 17 percent (including produce from the West Bank, which was under Jordan's mandate at the time.).By the mid-1980s, agriculture's share of GNP in Jordan was only about 6 percent. In contrast, in Syria and Egypt agriculture constituted more than 20 percent of GNP in the 1980s. Several factors contributed to this downward trend. With the Israeli occupation of the West Bank, Jordan lost prime farmland that Jordan had been running since 1949. Starting in the mid-1970s, Jordanian labor emigration also hastened the decline of agriculture. Many Jordanian abandoned the land to take more lucrative jobs abroad. Others migrated to cities where labor shortages had led to higher wages for manual workers. Deserted farms were built over as urban areas expanded. As the Jordanian government drove up interest rates to attract remittance income, farm credit tightened, which made it difficult for farmers to buy seed and fertilizer.
In striking contrast to Egypt and Iraq, where redistribution of land irrigated by the Nile and Euphrates rivers was a pivotal political, social, and economic issue, land tenure was never an important concern in Jordan. More than 150,000 foreign laborers—mainly Egyptians—worked in Jordan in 1988, most on farms. Moreover, since the early 1960s, the government has continuously created irrigated farmland from what was previously arid desert, further reducing competition for arable land. Ownership of rain-fed land was not subject to special restrictions. Limited land reform occurred in the early 1960s when, as the government irrigated the Jordan River valley, it bought plots larger than twenty hectares (50 acres), subdivided them, and resold them to former tenants in three-hectare to five-hectare plots. Because the land had not been very valuable before the government irrigated it, this process was accomplished with little controversy. In general, the government has aimed to keep land in larger plots to encourage efficiency and mechanized farming. The government made permanently indivisible the irrigated land that it granted or sold so as to nullify traditional Islamic inheritance laws that tended to fragment land.Arger Fen
Arger Fen is a 49.7 hectare biological Site of Special Scientific Interest (SSSI) south-east of Sudbury in Suffolk, England. The site occupies two separate areas. The 17.6-hectare (43-acre) Arger Fen Local Nature Reserve is part of the larger eastern block, and contains part of the 21-hectare (52-acre) Tiger Hill Local Nature Reserve, along with part of the 110-hectare (270-acre) Arger Fen and Spouse's Vale, a nature reserve managed by the Suffolk Wildlife Trust. The site lies in the Dedham Vale Area of Outstanding Natural Beauty,The site is made up of a mix of woodland and meadow habitats with much of the woodland believed to be ancient in origin. The underlying geology is a mixture of sand and gravel banks and clay soils, producing a mix of habitat types, including wet fen type habitats at lower levels and dry grasslands on acidic soils on hill tops. It is one of only two known areas of ancient woodland in Eastern England which feature wild cherry (Prunus avium).Badgers are found on the reserve in a number of active setts. Other rare fauna include the hazel dormouse and barbastelle bat. In 2012 the reserve, which has ash trees at least 300 years old, was identified as a site of ash dieback and in 2013 it became a research site for Forestry Commission scientists studying genetic resistance to the Chalara fungus which causes the disease.There are onsite car parking facilities as well as two-way marked trails, including areas of board walk. The trust has attempted to encourage the growth of the dormouse population, partly by expanding the area of land it owns at Arger Fen.Braeburn Park
Braeburn Park is a 22.3 hectare nature reserve in Crayford in the London Borough of Bexley. It is managed by the London Wildlife Trust, and includes Wansunt Pit, a 1.9 hectare geological Site of Special Scientific Interest.The area was once used for market gardening; there were orchards, and the Old Crayford Gun Club had been based here. Later, like much of the nearby Dartford Heath, the site was extensively quarried (notably for sand), until it was finally infilled and abandoned in the 1980s; after which time it gradually reverted to nature. Habitats now include ruderal scrub, grassland and woodland. There is a wide variety of invertebrates, including rare ones such as skipping flower beetles and picture-winged flies. There is also a pond, and many common bird species. Reptiles catalogued here include the grass snake, common lizard and slow-worm. There is access to the reserve from Lower Station Road and Galloway Drive, Crayford.A large housing development called Braeburn Park was built here by Taylor Wimpey in 2000. A promised adjacent 17 hectare nature conservation area was finally added in 2014 thanks to resources and management provided by The Land Trust and London Wildlife Trust.Hackhurst and White Downs
Hackhurst and White Downs is a 185.1-hectare (457-acre) biological Site of Special Scientific Interest west of Dorking in Surrey. White Downs is a Nature Conservation Review site, Grade 2, and part of it is in the 200-hectare (490-acre) White Downs nature reserve, which is owned by the Wotton Estate and managed by the Surrey Wildlife Trust (SWT). Hackhurst Downs is a 29.9-hectare (74-acre) Local Nature Reserve, which part of the 40-hectare (99-acre) Hackhurst Downs nature reserve, which is owned by Surrey County Council and also managed by the SWT.This steeply sloping site is part of the North Downs escarpment, which has grassland, secondary woodland and scrub. It has a rich invertebrate fauna with forty species of butterfly, including adonis blue, chalkhill blue, brown hairstreak, Duke of Burgundy fritillary, marbled white and silver-spotted skipper.Lackford Lakes
Lackford Lakes is a 105.8 hectare biological Site of Special Scientific Interest (SSSI) north and east of Lackford in Suffolk. The SSSI is part of the 131 hectare Lackford Lakes nature reserve, which is managed by the Suffolk Wildlife Trust.The lakes are disused sand and gravel pits in the valley of the River Lark. There are diverse dragonfly species, and many breeding and overwintering birds, including nationally important numbers of gadwalls and shovelers. Skylarks breed on dry grassland, and lapwings in marshy meadows.There is access from the A1101 road.Lamorbey Park
Lamorbey Park is a 57 hectare park in Lamorbey, in the London Borough of Bexley, set around a Grade II listed mansion, Lamorbey House. The original 17th century estate consisted of 119 hectares, but over time sections of the estate have been separated for other uses, including two secondary schools (Chislehurst and Sidcup Grammar School and Hurstmere School), Rose Bruford College, and Sidcup Golf Club. The area of the park still in public ownership includes The Glade, a 7.4 hectare area of historic landscape laid in the 1920s with a large lake. The park was added to the Register of Historic Parks and Gardens of special historic interest in 1988.Maplewood Flats Conservation Area
The Maplewood Flats Conservation Area is a 126 hectare (310 acre) conservation area located in North Vancouver, British Columbia, Canada. The area is composed of a 96 hectare (237 acre) intertidal zone of mudflats and salt marsh, and a 30 hectare (74 acre) upland area. It is preserved by Port Metro Vancouver as one of their ecological land initiatives. The land is located approximately 2 km east of the Second Narrows Bridge along Burrard Inlet in North Vancouver (20 minute drive from Vancouver city centre).Parks and open spaces in the London Borough of Bexley
The London Borough of Bexley owns and maintains over 100 parks and open spaces within its boundaries, with a total of 638 hectares (1,580 acres). They include small gardens, river and woodland areas, and large parks with many sporting and other facilities.Ringstead Downs
Ringstead Downs is a 6.9-hectare (17-acre) biological Site of Special Scientific Interest east of Hunstanton in Norfolk. It is in the Norfolk Coast Area of Outstanding Natural Beauty, and it is the western part of the 11-hectare (27-acre) Ringstead Downs nature reserve, which is managed by the Norfolk Wildlife Trust.This is a dry chalk valley which was carved out by glacial meltwaters It is species-rich as it has never been ploughed, and it is the largest surviving area of chalk downland surviving in the county. The butterflies are diverse.A footpath between Ringstead and Downs Road in Hunstanton goes through the reserve.Seale Chalk Pit
Seale Chalk Pit is a 1.2-hectare (3.0-acre) geological Site of Special Scientific Interest west of Guildford in Surrey. It is a Geological Conservation Review site and part of the Seale Chalk Pit and Meadow 3-hectare (7.4-acre) private nature reserve, which is managed by the Surrey Wildlife Trust.This former quarry exposes rocks of the Hog’s Back, and exhibits the separation of the folding Mesozoic rocks of the Weald from the Tertiary sediments of the London Basin.The site is private land with no public access.Southrepps Common
Southrepps Common is a 5.6-hectare (14-acre) biological Site of Special Scientific Interest north of North Walsham in Norfolk. A larger area of 12.9-hectare (32-acre) is a Local Nature Reserve. It is owned by Southrepps Parish Council and managed by Southrepps Common Group. It is part of the Norfolk Valley Fens Special Area of Conservation.This is damp grassland and fen in the valley of the River Ant. There are several rare true flies characteristic of undisturbed wetlands, especially Pteromicra glabricula and Colobaea distincta, both of which have larvae which are parasitic on snails.The site is open to the publicSyderstone Common
Syderstone Common is a 43.7-hectare (108-acre) biological Site of Special Scientific Interest west of Fakenham in Norfolk. An area of 24-hectare (59-acre) is managed by the Norfolk Wildlife TrustThe common has heath and grassland areas in the valley of the River Tat. Pools on sand and gravel provide suitable habitats for five species of breeding amphibians, including the nationally rare natterjack toad.The site is open to the public.Thane
Thane, colloquially called Thana, is a metropolitan city in India. Thane city coincides entirely within Thane taluka, one of the seven talukas of Thane district; also, it is the headquarter of the namesake district. With a population of 1,841,488 distributed over a land area of about 147 square kilometres (57 sq mi), Thane city is the 16th most populated city in India with a population of 18.9 Lakhs according to the 2011 census. The city is also called "City of Lakes" as the city is surrounded by 35 lakes.
Located on the northwestern side of the state of Maharashtra, the city is an immediate neighbour of Mumbai city and a part of the Mumbai Metropolitan Region, one of the most populous urban agglomerations in the world.Totteridge Fields
Totteridge Fields is a 97-hectare Site of Metropolitan Importance for Nature Conservation (SINC) in Totteridge in the London Borough of Barnet. The SINC includes the privately owned Highwood Hill, and at the western end is a seven-hectare Local Nature Reserve owned by Barnet Council and managed by the London Wildlife Trust.The Local Nature Reserve is an ancient hay meadow habitat consisting of three fields, known as Nutt Field, Hen Mead and Nearer Slay Land, with hawthorn and blackthorn hedgerows. The entrance is on Hendon Wood Lane, Arkley.The main part of the site consists of a large area of uncultivated grassland and old hedgerows between Totteridge Common and Mays Lane, crossing Dollis Brook, which is also an SINC. The grassland has a wide range of wildflowers, such as sneezewort and harebell. The site also hosts the declining skylark and several rare beetles and spiders.The Dollis Valley Greenwalk and London Loop cross Totteridge Fields.Trumpeter Islets
The Trumpeter Islets comprise a group of two unpopulated islets, with a combined area of about a hectare, located close to the south-western coast of Tasmania, Australia. Situated some 6 kilometres (3.7 mi) where the mouth of Port Davey meets the Southern Ocean, the 1-hectare (2.5-acre) island is part of the Trumpeter Islets Group, and comprises part of the Southwest National Park and the Tasmanian Wilderness World Heritage Site.Wansford Pasture
Wansford Pasture is a 3.1 hectare biological Site of Special Scientific Interest in Wansford in Cambridgeshire. It is part of the 7.3 hectare Wansford Pasture & Standen's Pasture, a nature reserve managed by the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire (WTBCN).This is a south-facing slope, with Jurassic limestone grassland and a flush lower down which has a wide variety of wet-loving plants, including some which are rare in the county. The ecology is maintained by avoiding the use of fertilisers and herbicides, and by grazing. The WTBCN was enlarged by the donation of Standen's Pasture in 2007.There is access to the site from Old Leicester Road.Waresley and Gransden Woods
Waresley and Gransden Woods is a 50 hectare nature reserve between Waresley and Great Gransden in Cambridgeshire, England. It is managed by the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire. The site is a 54.2 hectare biological Site of Special Scientific Interest called Waresley Wood, with slightly different boundaries (but including Gransden Wood).This ancient woodland is mainly ash, field maple and hazel. There are also rides with diverse flora such as the herbs bush vetch, meadowsweet, greater burnet-saxifrage and self-heal.There is access by a path from Waresley Road.
|Derived units |
with special names
|Other accepted units|