Comparison of Area units

Unit	SI	SI base
1 ca	1 m2	1 m2
1 a	1 dam2	102 m2
1 ha	1 hm2	104 m2
100 ha	1 km2	106 m2
non-SI comparisons
non-SI	metric	SI base
0.00386102 sq mi	1 ha	104 m2
2.471 acre	1 ha	104 m2
107,639 sq ft	1 ha	104 m2

A hectare (symbol ha, pronounced /ˈhɛktɛər/) is a unit of area equal to 10,000 square metres (107,639 sq ft), or one square hectometre (100 metres, squared), and is commonly used for measuring land area.

The hectare is used in most countries around the world^{[citation needed]}, especially in domains concerned with land ownership, land planning, and management, including law (land deeds), agriculture, forestry, and town planning. In similar applications, the United States, Great Britain, Ireland^{[citation needed]}, Myanmar, and to some extent Canada instead use the Imperial measurement acre, which equals 0.404686 ha. Some of the former Ottoman countries and Norway use the decare, one tenth of a hectare.^{[citation needed]}

Its base unit, the are, was defined by older forms of the metric system, but is no longer part of the modern metric system. The The International Committee for Weights and Measures classifies the hectare as a unit that is accepted for use with SI.^[1]

Even in countries that have undergone a general conversion from traditional English measurements to metric measurements (e.g. Canada), legal descriptions relating to land, which frequently use the acre, have not been converted, as doing so would require a resurvey of the land, an activity which would destabilize the security of land titles.^{[citation needed]}

Contents 1 International use 2 Conversions 2.1 Metric 2.2 Imperial units 2.3 Other 3 See also 4 References 5 External links

[edit] International use

The hectare has been subsequently defined in a number of nations by a country-specific term. In each of the following, the national unit of area has been defined as one hectare:^[2]

• jerib in Iran
• gong qing in mainland China
• manzana in Argentina
• bunder in The Netherlands

[edit] Conversions

One hectare is equivalent to:

[edit] Metric

• 10,000 square metres
• 0.01 square kilometre
• 1 square hectometre
• 10 decares
• 100 ares
• 10,000 centiares

[edit] Imperial units

• 2.4710538 international acres
• 2.4710439 U.S. survey acres
• 107,639 square feet
• 0.00386102 square miles (statute)

[edit] Other

• 15 mǔ (Chinese)
• 0.15 qǐng
• 10 dunam or dönüm (Middle East)
• 10 stremmata (Greece)
• 6.25 rai (Thai)
• ≈ 1.008 chō (Japanese)
• 7.47 bigha (Bangladesh, India,Nepal)

[edit] See also

• 1 E+4 m² for further comparisons
• conversion of units
• hecto-
• Hectometre
• Orders of magnitude

[edit] References

[edit] External links

• Official SI website: Table 6. Non-SI units accepted for use with the International System of Units
• Agricultural Measurements and Conversions