Area Unit Converter – Check All 296 Units

Type a number in the Convert from field and pick its unit from the list below the field, then pick the unit you want below the Convert to field. The converter starts with acres and hectares, and the result appears as you type. It also works the other way round: type a number in the Convert to field and the converter fills in the first one.

Both lists hold the same 296 units in 37 groups. The most used units come first, followed by imperial and US customary units, US survey and building units, metric units and old British and Irish land measures. After them come wire sizes, physics, old units from the rest of Europe and Latin America, Asian units, ancient and biblical units, and regional units still in use today.

You don't have to look for the unit in the list. Type it after the number, for example “1,500 sq ft”, “2.5 acres” or “10 ha”, and the converter sets the unit below the field and tells you which one it picked. The field reads both spellings, so “square metre” and “square meter” set the same unit. Land written in two units, such as “2 acres 1 rood”, turns into one value: here 2.25 acres.

Many land measures had a different size in each country or province. If you type just “1 morgen” or “1 arpent”, the converter picks the most common version and says below the field that the list has others. For old and regional units, a line below the fields also shows where and when the unit was used and its value in square metres. When the sources don't agree on one value, the line gives the value we calculate with and the range the sources give, and the result has only as many digits as the sources support.

The Copy result button copies the number from the Convert to field, and Clear all empties both fields.

One acre is 0.40468564224 ha, or about 0.4047 ha, and one hectare is about 2.471 acres. To turn acres into hectares in your head, multiply by 0.4. To go from hectares to acres, multiply by about 2.5.

An acre is 43,560 ft², 4,840 yd² or 4,046.8564224 m². It is traditionally the area of one chain by one furlong, 66 by 660 feet, and in the Middle Ages it was thought of as the land one man could plough with a team of eight oxen in a day. An acre has no fixed shape, but as a square it would be about 208 feet 9 inches on each side[1].

A hectare is a square 100 metres on each side, 10,000 m². Its name joins “hecto”, a hundred, with the are, which the French defined as 100 m² when they introduced the metric system in 1795. The hectare is the land unit in the European Union, South Africa, New Zealand, Australia, Canada and the United Kingdom, while the United States measures land in acres[2].

In practice the two units live side by side. UK land registries have used hectares for new registrations for many years[3]. In Australia, homes and commercial property are advertised in square metres or hectares, but rural land is still sometimes reported in acres[4]. In Ireland the hectare is the legal unit, yet the statute acre is still widely used, especially in farming[1].

Sports fields help to picture these sizes. An American football field, end zones included, is 360 by 160 feet[5], which is 57,600 ft², or about 1.32 acres. FIFA recommends a soccer pitch of 105 by 68 metres[6]. That is 0.714 ha, or about 1.76 acres, so a hectare is a little larger than such a pitch.

Multiply square feet by 0.09290304 to get square metres. To go the other way, multiply square metres by about 10.7639. A room of 12 by 15 feet has 180 square feet of floor, which is about 16.72 m².

The factor comes from squaring a length. Since 1959 the foot has been exactly 0.3048 metres[7], so a square one foot on each side is 0.3048 × 0.3048 = 0.09290304 m². The same rule works for every unit of area: square the length factor. A yard is 3 feet, so a square yard is 3 × 3 = 9 ft². A kilometre is 1,000 metres, so a square kilometre is 1,000,000 m², or 100 ha. The SI rules say the same thing in their own way: in cm² the exponent applies to the whole centimetre, so 1 cm² is (0.01 m)², a ten-thousandth of a square metre[8]. Length factors themselves are in our length unit converter.

A square foot is the area of a square with 1-foot sides. In the United States and Canada it is the usual unit for the size of a home, an office or a room[9], and flooring, tiles and paint are often sold by how many square feet they cover. A square metre is the SI unit of area, the area of a square with 1-metre sides. UK and Australian floor plans and property listings give it as m² or sqm, and the field reads both.

The converter works with areas, not sides, so multiply the length by the width first and type the result. When a room isn't a rectangle, split it into rectangles, work out each one and add them up.

The imperial units of area are squares of the imperial units of length, and Britain's Weights and Measures Act 1985 lists them in one chain: a square foot is 144 square inches, a square yard is 9 square feet, a rood is 1,210 square yards, an acre is 4,840 square yards, and a square mile is 640 acres[10]. The US defines them the same way, and a square inch is exactly 6.4516 cm²[7].

The rod, also called the perch or the pole, is 16½ feet long[11]. A square rod is therefore 272¼ square feet, and 160 of them make an acre[12]. In land measures it is usually just called a perch. A rood is a quarter of an acre, 10,890 ft², or 40 perches, and in old documents it is sometimes written as “rod” with the same meaning[13]. Old British and Irish deeds give land in acres, roods and perches[13], and the Irish acre was likewise 160 square perches, only with a longer perch[14]. The field reads such entries: “2 acres 1 rood” gives 2.25 acres, and “3 roods 10 perches” gives 3.25 roods.

A square chain is 66 by 66 feet, a tenth of an acre, which made acres easy to count from a surveyor's chain[7]. The square furlong is 10 acres, and the square mile is 640 acres, about 2.59 km².

A section has 640 acres, one square mile, and a quarter section has 160 acres. These are the plots of the Public Land Survey System, which divides much of the United States into a grid. Thirty-six sections make up a survey township[15], a square nominally six miles on each side, or about 93.24 km²[16]. Under the Homestead Act of 1862 a settler could claim 160 acres, a quarter section, of public land[15]. Canada's Dominion Land Survey uses similar townships of about 36 square miles[16].

Real sections and townships are only nominally square. Handbook 44 marks their values as approximate[7], and the converter calculates with the definition: 640 acres for a section, 160 for a quarter section and 23,040 for a survey township.

For more than a century, US land surveys used a slightly different foot of exactly 1200/3937 metres, the US survey foot. NIST and NOAA have retired it: December 31, 2022 was its last day, and since January 1, 2023 the international foot of 0.3048 metres has replaced it[17]. The chain, the rod and the acre, which used to be defined only through the survey foot, now have a definition through the international foot as well[7]. A US survey acre is about 4,046.87261 m², bigger than the international acre by only about 0.016 m², roughly 25 square inches[1]. Old deeds and plats still give land in survey units, so the list keeps US survey square foot, US survey acre and US survey square mile.

In building, a roofing square is 100 square feet[7]. Roofing shingles, metal roofing and siding are sold by the square in the US and Canada[9]. Type “30 squares of roofing” and the converter sets this unit.

Every metric unit of area is a square metre with a prefix. Because the side is squared, each step on the length scale is a step of 100 on the area scale: 1 m² is 100 dm², 1 dm² is 100 cm², and 1 cm² is 100 mm². Square micrometres and square nanometres turn up in science and electronics.

For land, the metric system has the are and its multiples. A decare (daa) is 10 a, 1,000 m². The same 1,000 m² goes by local names. Greece and Cyprus call it the stremma[18], and in Israel, Palestine, Syria, Iraq and Turkey it is the metric dunam, adopted in Palestine in 1928[19]. Norway has the mål, which has meant 1,000 m² since the old mål of 10,000 Norwegian square feet was replaced[20].

Before the imperial acre spread across the British Isles, Scotland and Ireland had their own. The Scots acre was standardised in 1661 and gave way to the imperial acre after the Weights and Measures Act 1824. Its size is given as 5,080 m², or as 54,760 square feet, about 1.257 acres[21], and these two figures don't quite agree, so the converter treats it as approximate. The Irish acre came from a perch of 7 yards and was in use from the plantations of the 16th century until the 19th century[14]. It is about 1.62 statute acres. The Cheshire acre was even larger, 10,240 square yards[1].

The hide was originally the land that could support a household, and it became a measure of value and tax. Domesday Book of 1086 records estates in hides, and a hide was usually four virgates. In some counties it is shown as 120 acres, 30 to the virgate, but those were fiscal acres, units of tax assessment, not of area. The northern Danelaw used the carucate of eight bovates instead[22]. A bovate, or oxgang, averaged about 20 acres but could be as little as 15, depending on the land[23]. The converter gives these four units only two significant digits.

A circular mil is the area of a circle one mil, a thousandth of an inch, across, which is about 0.785398 of a square mil. The US National Electrical Code and the Canadian Electrical Code use it for wire sizes larger than 0000 AWG, and large wires are given in thousands of circular mils, written kcmil or MCM. One kcmil is about 0.5067 mm², so 2 kcmil is roughly 1 mm² with an error of 1.3%[24]. The field reads “250 kcmil” and “250 MCM” as the same unit.

The barn is 1 × 10⁻²⁸ m², roughly the cross-section of a uranium nucleus. Physicists use it for cross-sections of nuclear reactions and particle collisions[25]. The square ångström is the square of an ångström, a tenth of a nanometre.

The arpent is an old French unit that is still used in Quebec, in parts of the United States that belonged to French Louisiana, and in Mauritius and the Seychelles[26]. An arpent of area always had 100 square perches, but the perche was 18, 20 or 22 royal feet long, so France had several arpents[27]. Canada's Weights and Measures Act gives the arpent as 32,400 French square feet, with a French foot of 12.789 inches[28], which makes the arpent (Quebec) about 0.8448 acres.

In the United States the arpent varied by state: about 0.84628 acres in Louisiana and 0.8507 acres in Arkansas and Missouri[29]. The list has both, next to the Paris arpent (arpent de Paris), which the converter sets when you type just “arpent”. The vergée is 25 square perches, and the bonnier (Liège) and the bonnier (Nivelles) were land measures in what is now Belgium[30].

Spain counted land in fanegas, aranzadas, tahúllas and dozens of local units, and their size changed from province to province. In 1852 Spain published official tables that set each provincial unit against the metric system. The legal Castilian fanega, the fanega de marco real, had 9,216 square varas[31], about 1.591 acres. The converter takes this fanega when you type just “fanega”, and the other 56 units of the Old Spanish and Latin American group come from the same tables or from a 1926 survey of national measures[32].

Some of these units are still in use in Latin America. A manzana was originally 10,000 square varas: in Argentina it is now a hectare, and in most of Central America it is about 7,000 m², with a slightly different value in each country[33]. The converter sets the manzana (10,000 square varas) for a plain “manzana”, about 1.727 acres, and lists the national versions next to it. In Puerto Rico a cuerda is fixed by a 1968 law at 3,930.395625 m²[34], about 0.9712 acres, which is why it has been called a “Spanish acre” and treated as equal to an acre[35].

An alqueire paulista is 2.42 ha, about 5.98 acres. Brazil still trades farmland in alqueires, which are counted in braças of 2.2 metres: the alqueire paulista is 50 by 100 braças, and the alqueire mineiro is 100 by 100 braças, 4.84 ha[36]. A square braça is 4.84 m² and a Portuguese square vara 1.21 m²[37]. The tarefa, used in northeastern Brazil, was 30 to 40 ares[32].

The morgen took its name from the land that could be ploughed in one morning, and its size varied by region, usually between a fifth and a half of a hectare[38]. In Prussia, the order of 1816 set the morgen at 180 Prussian square rods, and a Hufe at 30 morgen[39]. That Prussian morgen (Magdeburg) is about 2,553.22 m², and the converter picks it when you type just “morgen”. Bavaria measured fields in the Tagwerk of 400 square rods, divided into 100 Dezimal[40].

In 1869 the North German Confederation introduced a metric morgen of a quarter hectare. German farmers still use the modern Morgen (25 ares): in 2015 the average farm had 59.6 hectares, or 238.4 morgen[38]. In the Netherlands the Rhineland morgen had 600 square rods, and in South Africa the morgen was the legal land unit of the Cape, the Orange Free State and the Transvaal until metrication in the 1970s. In 2007 the Law Society of South Africa published a factor of 0.856532 hectares per morgen[38][41].

Austria measured land in the Joch of 1,600 square Klafter, and with the Viennese Klafter fixed by a law of 1871 a Joch is about 5,754.64 m²[42], about 1.422 acres. Hungary used the same area as the cadastral hold, with the square Klafter as the négyszögöl[43]. In the Czech lands these Viennese measures applied from 1765 to 1876: the jitro was the Joch, the korec was half of it and the měřice a third[44]. The older Czech lán came in several kinds, from the land lán to the royal lán[45].

In German-speaking Switzerland the Juchart was standardised at 36 ares in 1838, Vaud set its pose at 45 ares in 1822, and Ticino its pertica at 5 ares in 1826[46]. The Mannwerk, or Tagwan, was an estimate for meadows of 29 to 32 ares[47].

Old Polish land measures were counted in square ells, so their size in metres depends on which ell was used. A morga had 16,875 square ells and a włóka 30 morgas[48]. In Congress Poland the New Polish measures of 1819 fixed the morga at 300 square rods, 5,598.72 m²[49], and the converter sets this morga when you type just “morga”.

In Russia, land was measured in desyatinas. Surveying instructions of 1753 set the desyatina at 2,400 square sazhens, and the economic desyatina was 80 by 40 sazhens, 3,200 square sazhens[50]. A square sazhen is 9 square arshins or 49 square feet, and a square verst is 250,000 square sazhens[51]. A desyatina is about 1.093 ha.

Scandinavia measured fields by the barrel of land, the area sown with a barrel of seed. Denmark's tønde land had 14,000 square ells from 1683 until it was abolished in 1907[52]. Sweden's tunnland had 56,000 Swedish square feet[53], and Norway's tønneland was 40,000 Norwegian square feet[53].

Each Italian province had its own measures until Italy published tables in 1877 that set them against the metric system[54]. Farmers in some regions still name land in them: the Milanese pertica around Milan is 654.5179 m²[55], while a biolca or a campo means a different area in each province.

The Ottoman dunam was the land a team of oxen could plough in a day. Through the early British Mandate it measured 919.3 m² in Palestine, and Cyprus used a donum of 14,400 square feet[19].

A tsubo (坪) is exactly 400/121 m², about 3.30579 m², and Japanese law defines the se as 30 tsubo, the tan as 300 and the chō as 3,000[56]. Japanese home listings also count rooms in jō, the size of a tatami mat, and the rules for real estate advertising treat one jō as at least 1.62 m²[57]. That is the value the converter uses for the jō (tatami mat).

The Chinese mu (亩) is 6,000 square chi with a chi of a third of a metre, about 666.667 m², and a qing is 100 mu[58]. Fifteen mu make a hectare. In Thailand a rai (ไร่) is 1,600 m², 4 ngan or 400 square wa, and land documents give areas in these units[59]. Vietnamese units differed between the north and the centre of the country[60], and the công of the southwest is 1,000 m²[60]. The Indonesian bahu, or bouw, of Java had no single value[32].

In India, Pakistan and Bangladesh the bigha has no standard size and changes from region to region. In Punjab and Haryana two bighas make an acre, a bigha has 4 kanals and a kanal 20 marlas[61]. In southern India land is sold by the cent, a hundredth of an acre[62], which is 435.6 ft². The converter sets the pucca bigha (Rajasthan, Uttar Pradesh, Bihar) when you type just “bigha” and lists the other versions next to it.

The feddan is the only non-metric unit that Egypt kept after adopting the metric system. It is divided into 24 kirats[63], and the converter counts it as about 1.038 acres. In Afghanistan a jerib is 2,000 m²[64].

The jugerum was the usual Roman land measure, 240 by 120 Roman feet. Half of it was the actus quadratus of 120 by 120 feet, two jugera made a heredium, 100 heredia a centuria, and 4 centuriae a saltus[65]. With a Roman foot of about 0.296 m the jugerum comes to about 0.624 acres. In Greece the plethron squared was 10,000 square feet and the aroura a quarter of it[66].

Egyptian surveyors measured fields in the setat, a square khet of 100 by 100 cubits, and the Palermo Stone records land grants in kha and setat[67]. In Mesopotamia the basic unit was the sar, a garden plot of about 36 m², and 100 sar made an iku[68].

The Bible describes fields by how much seed they take, and the closest thing to a unit is the tsemed, the land a yoke of oxen could plough in a day (Isaiah 5:10)[69]. The Mishnah and Talmud count in beit se'ah, a field sown with one se'ah of seed. The Jewish Encyclopedia puts it at 2,500 square cubits[70], which the converter turns into about 785 m², while other estimates range from 576 to 829.5 m²[69].