Hectare
Metric unit of area equal to 10,000 square metres.
The hectare (SI symbol: ha) is a non-SI metric unit of area equal to 10,000 square metres (1 hm²), primarily used for land measurement. One hectare corresponds to a square with sides of 100 metres, and there are 100 hectares in a single square kilometre. For comparison, an acre is smaller than a hectare, and a hectare is roughly two and a half times the size of an acre. The playing field used in Gaelic football and hurling, such as at St. Enda's GAA ground in Omagh, is a little over a hectare in area, and Trafalgar Square in London has an area of about one hectare.
The unit’s name was coined in French, derived from Latin. It was introduced in 1795 when the French Revolutionary government established the metric system, defining the are as 100 square metres (one square decametre). The hectare, combining the prefix "hecto-" with "are," thus equalled 100 ares, or 10,000 square metres. When the metric system was rationalised into the International System of Units (SI) in 1960, the are was not included as a recognised unit. Consequently, from 2026, the International Bureau of Weights and Measures (BIPM) no longer describes the hectare as accepted for use with the SI, though it remains widely used.
The hectare is the legal unit for land measurement in domains such as law, agriculture, forestry, and town planning across the European Union, South Africa, New Zealand, Australia, Canada, and the United Kingdom. The United States and Myanmar, however, continue to use the acre. In many countries, metrification redefined existing land measures as exactly one hectare, including the jerib in Iran, the djerib in Turkey, the gongqing in China, the manzana in Argentina, and the bunder in the Netherlands (until 1937). In Mexico, land areas are commonly expressed as combinations of hectares, ares, and centiares, written with hyphens (e.g., 1-21-00.26 ha). The centiare equals one square metre, while the rarely used deciare is ten square metres. The decare, equal to 10 ares or 1,000 square metres, is used in Norway and former Ottoman regions. In Russia, the are is called a sotka (meaning "a hundred") and is used for suburban plots.
- unit_type
- Area
- symbol
- ha
- value_in_SI
- 10,000 m² (1 hm²)
- primary_use
- Land measurement
- common_equivalents
- 2.47 acres; 100 hectares per km²
Lore & Background
The hectare is a metric unit of area, defined as a square with sides of 100 metres, equivalent to 10,000 square metres or one square hectometre. Its name originates from the French language, derived from the Latin word 'ārea'. The unit is widely employed globally for measuring large land areas, particularly in legal contexts such as land deeds, as well as in agriculture, forestry, and town planning. It is the official unit of land measurement throughout the European Union, South Africa, New Zealand, Australia, Canada, and the United Kingdom. In contrast, the United States and Myanmar continue to use the acre. In several countries, traditional land measures have been redefined to equal exactly one hectare; examples include the jerib in Iran, the djerib in Turkey, the gongqing in China, the manzana in Argentina, and the bunder in the Netherlands until 1937. In Mexico, land areas are often expressed as combinations of hectares, ares, and centiares, written with hyphens. The hectare is part of a family of units derived from the are, which was originally defined in 1795 as 100 square metres. The are itself is still used in some regions, such as Indonesia, India, and parts of Europe, while in Russia and former Soviet states it is called a 'sotka' (meaning one hundred), commonly used for garden plots. The decare, equal to 10 ares or 1,000 square metres, is used in Norway and parts of the Middle East and Bulgaria. The centiare is one square metre, and the rarely used deciare equals ten square metres. A non-standard unit, the decimilliare, equals one square decimetre.
Reader's Guide
The hectare is a foundational unit for land measurement across much of the world, serving as the legal unit in domains such as law (land deeds), agriculture, forestry, and town planning throughout the European Union, South Africa, New Zealand, Australia, Canada, and the United Kingdom. In contrast, the United States and Myanmar use the acre. In Mexico, land areas are commonly given as combinations of hectares, ares, and centiares. The hectare's family includes the centiare (1 m²), deciare (10 m²), are (100 m²), and decare (1,000 m²), with the decare used in Norway and former Ottoman areas. Despite its exclusion from SI, the hectare remains essential for practical land measurement globally.
Did You Know?
- One hectare is equivalent to 2.47 acres.
- In Mexico, land areas are commonly written as hyphen-separated combinations of hectares, ares, and centiares.
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