Hectare
metric unit of area
The hectare (; SI symbol: ha) is a non-SI metric unit of area 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. An acre is about 0.405 hectares and thus one hectare is about 2.47 acres.
In 1795, when the metric system was introduced, the are was defined as 100 square metres, or one square decametre, and the hectare ("hecto-" + "are") was thus 100 ares or 1/100 km2 (10000 square metres). 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, and from 2026 the hectare is no longer described by the International Bureau of Weights and Measures (BIPM) as accepted for use with the SI.
Description
The name was coined in French, from the Latin ārea. The hectare is equivalent to 10,000 square metres (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 some domains concerned with land ownership, planning, and management, including law (land deeds), agriculture, forestry, and town planning throughout the European Union, South Africa, New Zealand, Australia, Canada and the United Kingdom.
However, the United States and Myanmar (Burma) use the acre 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:
Jerib (Persian: جریب) in Iran
Djerib (Turkish: cerip) in Turkey
Gongqing (traditional Chinese: 公頃; simplified Chinese: 公顷; pinyin: gōngqǐng) in China
Manzana in Argentina
Bunder in the Netherlands (until 1937)
In Mexico, land area measurements are commonly given as combinations of hectares, ares, and centiares.
The public source identifies “Hectare” as metric unit of area. This brief keeps that definition visible, then builds a research path around Hectare, metric and unit.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Hectare”, the useful work is to connect “metric unit of area” to the records capable of establishing context and consequence.
Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Aug 11, 2026. The linked authority identifier is Q35852. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1795, 1960, 2026 and 1937.
A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Hectare”, its source revision and the description used here.
- Expand the search: follow Hectare primary sources, Hectare archive and Hectare research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Hectare”?
- Which cited source is closest to the event, object or claim?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “Hectare” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.