Acre
Overview
 
The acre is a unit
Units of measurement
A unit of measurement is a definite magnitude of a physical quantity, defined and adopted by convention and/or by law, that is used as a standard for measurement of the same physical quantity. Any other value of the physical quantity can be expressed as a simple multiple of the unit of...

 of area
Area
Area is a quantity that expresses the extent of a two-dimensional surface or shape in the plane. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat...

 in a number of different systems, including the imperial and U.S. customary systems. The most commonly used acres today are the international acre and, in the United States, the survey acre. The most common use of the acre is to measure tracts of land.

The acre is related to the square mile
Square mile
The square mile is an imperial and US unit of measure for an area equal to the area of a square of one statute mile. It should not be confused with miles square, which refers to the number of miles on each side squared...

, with 640 acres making up one square mile. One mile is 5280 feet (1760 yards).
Encyclopedia
The acre is a unit
Units of measurement
A unit of measurement is a definite magnitude of a physical quantity, defined and adopted by convention and/or by law, that is used as a standard for measurement of the same physical quantity. Any other value of the physical quantity can be expressed as a simple multiple of the unit of...

 of area
Area
Area is a quantity that expresses the extent of a two-dimensional surface or shape in the plane. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat...

 in a number of different systems, including the imperial and U.S. customary systems. The most commonly used acres today are the international acre and, in the United States, the survey acre. The most common use of the acre is to measure tracts of land.

The acre is related to the square mile
Square mile
The square mile is an imperial and US unit of measure for an area equal to the area of a square of one statute mile. It should not be confused with miles square, which refers to the number of miles on each side squared...

, with 640 acres making up one square mile. One mile is 5280 feet (1760 yards). Divisions of land area were typically based on the square mile, and fractions thereof. If the square mile is divided into quarters, each quarter has a side length of 1/2 mile (880 yards) and is 1/4 square mile in area, or 160 acres. These subunits would typically then again be divided into quarters, with each side being 1/4 mile long, and being 1/16th of a square mile in area, or 40 acres. In the United States, farmland was typically divided as such, and the phrase "the back 40" would refer to the 40 acre parcel to the back of the farm. Most of the US midwest is on square mile grids for surveying purposes.

One acre comprises 4,840 square yard
Square yard
The square yard is an imperial/US customary unit of area, formerly used in most of the English-speaking world but now generally replaced by the square metre outside of the U.S., Canada and the U.K. It is defined as the area of a square with sides of one yard in length...

s, 43,560 square feet
Square foot
The square foot is an imperial unit and U.S. customary unit of area, used mainly in the United States, Canada, United Kingdom, Hong Kong, Bangladesh, India, Pakistan and Afghanistan. It is defined as the area of a square with sides of 1 foot in length...

 or about 4047 square metre (0.4047 ha) (see below). While all modern variants of the acre contain 4,840 square yards, there are alternative definitions of a yard, so the exact size of an acre depends on which yard it is based on. Originally, an acre was understood as a selion
Selion
Selion is a mediaeval open strip of land or small field used for growing crops, usually owned by or rented to peasants. A selion of land was typically one furlong long and one chain wide. However, exact measurements could vary depending on geography of the land. The area of one furlong by one...

 of land sized at one furlong
Furlong
A furlong is a measure of distance in imperial units and U.S. customary units equal to one-eighth of a mile, equivalent to 220 yards, 660 feet, 40 rods, or 10 chains. The exact value of the furlong varies slightly among English-speaking countries....

 (660 ft) long and one chain (66 ft) wide; this may have also been understood as an approximation of the amount of land an ox
Ox
An ox , also known as a bullock in Australia, New Zealand and India, is a bovine trained as a draft animal. Oxen are commonly castrated adult male cattle; castration makes the animals more tractable...

 could plough in one day. A square
Square (geometry)
In geometry, a square is a regular quadrilateral. This means that it has four equal sides and four equal angles...

 enclosing one acre is approximately 69.57 yards, or 208 in 9 in (63.63 m) on a side. As a unit of measure, an acre has no prescribed shape; any perimeter enclosing 43,560 square feet is an acre in size.

The acre is often used to express areas of land in the U.S and in countries where the Imperial System is still in use. , the acre is not used officially in the United Kingdom. In the metric system
Metric system
The metric system is an international decimalised system of measurement. France was first to adopt a metric system, in 1799, and a metric system is now the official system of measurement, used in almost every country in the world...

, the hectare
Hectare
The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...

 is commonly used for the same purpose. An acre is approximately 40% of a hectare.

Perhaps the easiest way to envisage an acre is as a rectangle measuring 88 yards by 55 yards (1/10 of 880 yards by 1/16 of 880 yards), approximately the size of a standard American football field. To be more exact, one acre is 90.75 percent of a 100 yards (91.44 m) long by 53.33 yards (48.8 m) wide American football field (without the end zones). The full field, including the end zones, covers approximately 1.32 acre (0.53418552 ha). The acre is also approximately 56.68 percent of a 105 metres (344.49 ft) long by 68 metres (223.1 ft) wide Association football (soccer) pitch
Association football pitch
An association football pitch is the playing surface for the game of association football made of turf. Its dimensions and markings are defined by Law 1 of the Laws of the Game, "The Field of Play".All line markings on the pitch form part of the area which they define...

. It may also be remembered as 44,000 square feet, less 1%; or as the product of 66 x 660.

International acre

In 1958, the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and countries of the Commonwealth of Nations
Commonwealth of Nations
The Commonwealth of Nations, normally referred to as the Commonwealth and formerly known as the British Commonwealth, is an intergovernmental organisation of fifty-four independent member states...

 defined the length of the international yard
Yard
A yard is a unit of length in several different systems including English units, Imperial units and United States customary units. It is equal to 3 feet or 36 inches...

 to be 0.9144 metre
Metre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...

s. Consequently, the international acre is exactly 4,046.8564224 square metre
Square metre
The square metre or square meter is the SI derived unit of area, with symbol m2 . It is defined as the area of a square whose sides measure exactly one metre...

s. Since the difference between the U.S. and International acre is only approximately 0.016 square metres (24.8 square inches), it is usually not important which one is being discussed.

United States survey acre

The United States survey acre is approximately 4,046.872 609 874 252 square metres; its exact value ( m2) is based on an inch defined by 1 metre = 39.37 inches exactly, as established by the Mendenhall Order
Mendenhall Order
The Mendenhall Order marked a decision to change the fundamental standards of length and mass of the United States from the customary standards based on those of England to metric standards. It was issued on April 5, 1893 by Thomas Corwin Mendenhall, superintendent of the U.S...

.

In India

In India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, especially in Kerala
Kerala
or Keralam is an Indian state located on the Malabar coast of south-west India. It was created on 1 November 1956 by the States Reorganisation Act by combining various Malayalam speaking regions....

 and Andhra Pradesh, Cent is a measurement used in measuring residential plots. One Cent is one-hundredth of an Acre.
  • 100 cents = 1 acre
  • 1 cent = acre
  • 1 cent = 40.468 sq.meter (m2)
  • 1 cent = 435.60 sq.feet (ft2)

Equivalence to other units of area

1 international acre is equal to the following metric units:
  • 4,046.8564224 square metres
  • 0.40468564224 hectare
    Hectare
    The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...

     (A square with 100 m sides has an area of 1 hectare.)


1 United States survey acre is equal to:
  • 4,046.87261 square metres
  • 0.404687261 hectare
    Hectare
    The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...



1 acre (both variants) is equal to the following customary units:
  • 66 feet × 660 feet (43,560 square feet
    Square foot
    The square foot is an imperial unit and U.S. customary unit of area, used mainly in the United States, Canada, United Kingdom, Hong Kong, Bangladesh, India, Pakistan and Afghanistan. It is defined as the area of a square with sides of 1 foot in length...

    )
  • 1 chain × 10 chains (1 chain = 66 feet = 22 yards = 4 rods = 100 links)
  • 1 acre is approximately 208.71 feet × 208.71 feet (a square)
  • 4,840 square yards
  • 160 perches. A perch is equal to a square rod (1 square rod is 0.00625 acre)
  • 10 square chains
  • 4 roods
    Rood (measurement)
    Rood has several distinct meanings, all derived from the same basic etymology. The most significant are an obsolete English measure of area, an obsolete English measure of length, and a term for a cross or crucifix, especially a large one displayed in a church....

  • A chain by a furlong (chain 22 yards, furlong 220 yards)
  • 1/640 (0.0015625) square mile
    Square mile
    The square mile is an imperial and US unit of measure for an area equal to the area of a square of one statute mile. It should not be confused with miles square, which refers to the number of miles on each side squared...

     (1 square mile is equal to 640 acres)

Historical origin

The word "acre" is derived from Old English æcer originally meaning "open field", cognate
Cognate
In linguistics, cognates are words that have a common etymological origin. This learned term derives from the Latin cognatus . Cognates within the same language are called doublets. Strictly speaking, loanwords from another language are usually not meant by the term, e.g...

 to west coast Norwegian ækre and Swedish
Swedish language
Swedish is a North Germanic language, spoken by approximately 10 million people, predominantly in Sweden and parts of Finland, especially along its coast and on the Åland islands. It is largely mutually intelligible with Norwegian and Danish...

 åker, German
German language
German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....

 Acker, Dutch
Dutch language
Dutch is a West Germanic language and the native language of the majority of the population of the Netherlands, Belgium, and Suriname, the three member states of the Dutch Language Union. Most speakers live in the European Union, where it is a first language for about 23 million and a second...

 akker, Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 ager, and Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 αγρός (agros).

The acre was approximately the amount of land tillable by one man behind an ox
Ox
An ox , also known as a bullock in Australia, New Zealand and India, is a bovine trained as a draft animal. Oxen are commonly castrated adult male cattle; castration makes the animals more tractable...

 in one day
Day
A day is a unit of time, commonly defined as an interval equal to 24 hours. It also can mean that portion of the full day during which a location is illuminated by the light of the sun...

. This explains one definition as the area of a rectangle with sides of length one chain and one furlong
Furlong
A furlong is a measure of distance in imperial units and U.S. customary units equal to one-eighth of a mile, equivalent to 220 yards, 660 feet, 40 rods, or 10 chains. The exact value of the furlong varies slightly among English-speaking countries....

. A long narrow strip of land is more efficient to plough than a square plot, since the plough does not have to be turned so often. The word "furlong" itself derives from the fact that it is one furrow
Plough
The plough or plow is a tool used in farming for initial cultivation of soil in preparation for sowing seed or planting. It has been a basic instrument for most of recorded history, and represents one of the major advances in agriculture...

 long
.

Before the enactment of the metric system
Metric system
The metric system is an international decimalised system of measurement. France was first to adopt a metric system, in 1799, and a metric system is now the official system of measurement, used in almost every country in the world...

, many countries in Europe used their own official acres. These were differently sized in different countries, for instance, the historical French acre was 4,221 square metres, whereas in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 as many variants of "acre" existed as there were German states.

Statutory values for the acre were enacted in England by acts of:
  • Edward I
    Edward I of England
    Edward I , also known as Edward Longshanks and the Hammer of the Scots, was King of England from 1272 to 1307. The first son of Henry III, Edward was involved early in the political intrigues of his father's reign, which included an outright rebellion by the English barons...

    ,
  • Edward III
    Edward III of England
    Edward III was King of England from 1327 until his death and is noted for his military success. Restoring royal authority after the disastrous reign of his father, Edward II, Edward III went on to transform the Kingdom of England into one of the most formidable military powers in Europe...

    ,
  • Henry VIII
    Henry VIII of England
    Henry VIII was King of England from 21 April 1509 until his death. He was Lord, and later King, of Ireland, as well as continuing the nominal claim by the English monarchs to the Kingdom of France...

    ,
  • George IV
    George IV of the United Kingdom
    George IV was the King of the United Kingdom of Great Britain and Ireland and also of Hanover from the death of his father, George III, on 29 January 1820 until his own death ten years later...

     and
  • Queen Victoria – the British Weights and Measures Act
    Weights and Measures Act
    A Weights and Measures Act is an Act of Parliament determining trade law where the weight or size of the goods being traded are important. For example, if a bottle of milk is for sale and has a label saying it contains one pint, then the law states that it must contain that amount.-United...

     of 1878 defined it as containing 4,840 square yards.


Historically, the size of farms and landed estates in the United Kingdom was usually expressed in acres (or acres, rood
Rood (measurement)
Rood has several distinct meanings, all derived from the same basic etymology. The most significant are an obsolete English measure of area, an obsolete English measure of length, and a term for a cross or crucifix, especially a large one displayed in a church....

s, and perches), even if the number of acres was so large that it might conveniently have been expressed in square miles. For example, a certain landowner might have been said to own 32,000 acres of land, not 50 square miles of land.

Customary acre

The customary acre was a measure of roughly similar size to the acre described above, but it was subject to considerable local variation similar to the variation found in carucate
Carucate
The carucate or ploughland was a unit of assessment for tax used in most Danelaw counties of England, and is found for example in Domesday Book. The carucate was based on the area a plough team of eight oxen could till in a single annual season...

s, virgate
Virgate
The virgate or yardland was a unit of land area measurement used in medieval England, typically outside the Danelaw, and was held to be the amount of land that a team of two oxen could plough in a single annual season. It was equivalent to a quarter of a hide, so was nominally thirty acres...

s, bovates
Oxgang
An oxgang or bovate is an old land measurement formerly used in Scotland and England. It averaged around 20 English acres, but was based on land fertility and cultivation, and so could be as low as 15.Skene in Celtic Scotland says:...

, nooks, and farundels. However, there were more ancient measures that were also farthingales. These may have been multiples of the customary acre, rather than the statute acre.

Other acres

  • Scottish acre
    Acre (Scots)
    A Scottish acre was a land measurement used in the country. It was standardised in 1661. English acres were imposed in 1824 by an Act of Parliament, and the metric system is also used in Scotland.Equivalent to -* Scottish measures** 4 roods* Metric system...

    , one of a number of obsolete Scottish units of measurement
    Obsolete Scottish units of measurement
    Scotland had a distinct system of measures and weights until at least the late 18th century, based on the ell as a unit of length, the stone as a unit of mass and the boll and the firlot as units of dry measure...

  • Irish acre
    Acre (Irish)
    An Irish acre is a unit of area historically used in Ireland, Yorkshire, and regions bordering the Solway Firth.One Irish acre is equal to about 1.62 acre, 7,840 square yards, or 70,560 square feet....

    = 7,840 square yards
  • Cheshire acre
    Acre (Cheshire)
    A Cheshire acre is a unit of area historically used in the County of Cheshire.One Cheshire acre amounts to 10,240 square yards, or 92,160 square feet whereas a standard acre amounts to 4,840 square yards or 43,560 square feet...

    = 10,240 square yards
  • Roman acre
    Ancient Roman units of measurement
    The ancient Roman units of measurement were built on the Hellenic system with Egyptian, Hebrew, and Mesopotamian influences. The Roman units were comparatively consistent and well documented.-Length:Notes...

    = 1,260 square metres
  • God's Acre
    God's Acre
    God's Acre is an ancient Germanic designation for a burial ground. In his poem "God's-Acre," Henry Wadsworth Longfellow attributes the term to ancient Saxons.-In Christianity:...

     – a synonym for a churchyard.

See also

  • Anthropic units
    Anthropic units
    Anthropic units are units of measurement which explicitly arose from human physiology or behavior. Some were derived directly from the dimensions of the human body, and as such, are commonly referred to as anthropomorphic...

  • Conversion of units
    Conversion of units
    Conversion of units is the conversion between different units of measurement for the same quantity, typically through multiplicative conversion factors.- Process :...

  • Acre-foot
  • Spanish customary units
  • Quarter acre
    Quarter Acre
    In Australian and New Zealand English, a quarter acre is a term for a suburban plot of land. Traditionally, Australians and New Zealanders aspire to own a 3- or 4-bedroom house or bungalow on a section of around a quarter of an acre , also known locally as the Australian Dream or the New Zealand...

  • French arpent
    Arpent
    An arpent is a unit of length and a unit of area. It is a pre-metric French unit based on the Roman actus. It is used in Quebec as well as in some areas of the United States that were part of French Louisiana.-Unit of length:...

    —also used in Louisiana as length and area unit of measure
  • a Morgen
    Morgen
    A morgen was a unit of measurement of land in Germany, the Netherlands, Poland and the Dutch colonies, including South Africa and Taiwan. The size of a morgen varies from 1/2 to 2½ acres, which equals approximately 0.2 to 1 ha...

     ("morning") of land is usually set at 2/3 of a Tagwerk ("day work") of ploughing with an ox

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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