HOME

TheInfoList



OR:

The litre (international spelling) or liter (
American English American English, sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. English is the most widely spoken language in the United States and in most circumstances ...
spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of
volume Volume is a measure of occupied three-dimensional space. It is often quantified numerically using SI derived units (such as the cubic metre and litre) or by various imperial or US customary units (such as the gallon, quart, cubic inch). The ...
. It is equal to 1 cubic
decimetre The decimetre (symbol dm) or decimeter (American English) is a unit of length in the International System of Units (SI), equal to one tenth of a metre, ten centimetres, 100 millimetres or 3.937 inches. The common non-SI metric unit of volume ...
(dm3), 1000
cubic centimetre A cubic centimetre (or cubic centimeter in US English) (SI unit symbol: cm3; non-SI abbreviations: cc and ccm) is a commonly used unit of volume that corresponds to the volume of a cube that measures 1 cm × 1 cm × 1 cm. One cu ...
s (cm3) or 0.001
cubic metre The cubic metre (in Commonwealth English and international spelling as used by the International Bureau of Weights and Measures) or cubic meter (in American English) is the unit of volume in the International System of Units (SI). Its symbol is ...
(m3). A cubic decimetre (or litre) occupies a volume of (see figure) and is thus equal to one-thousandth of a cubic metre. The original French
metric system The metric system is a system of measurement that succeeded the decimalised system based on the metre that had been introduced in France in the 1790s. The historical development of these systems culminated in the definition of the Intern ...
used the litre as a base unit. The word ''litre'' is derived from an older French unit, the '' litron'', whose name came from Byzantine
Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...
—where it was a unit of weight, not volume—via Late Medieval Latin, and which equalled approximately 0.831 litres. The litre was also used in several subsequent versions of the metric system and is accepted for use with the SI,Bureau International des Poids et Mesures, 2006
p. 124. ("Days" and "hours" are examples of other non-SI units that SI accepts.)
although not an
SI unit The International System of Units, known by the international abbreviation SI in all languages and sometimes Pleonasm#Acronyms and initialisms, pleonastically as the SI system, is the modern form of the metric system and the world's most wid ...
—the SI unit of volume is the
cubic metre The cubic metre (in Commonwealth English and international spelling as used by the International Bureau of Weights and Measures) or cubic meter (in American English) is the unit of volume in the International System of Units (SI). Its symbol is ...
(m3). The spelling used by the
International Bureau of Weights and Measures The International Bureau of Weights and Measures (french: Bureau international des poids et mesures, BIPM) is an intergovernmental organisation, through which its 59 member-states act together on measurement standards in four areas: chemistry, ...
is "litre", a spelling which is shared by most English-speaking countries. The spelling "liter" is predominantly used in
American English American English, sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. English is the most widely spoken language in the United States and in most circumstances ...
. One litre of liquid water has a
mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different eleme ...
of almost exactly one
kilogram The kilogram (also kilogramme) is the unit of mass in the International System of Units (SI), having the unit symbol kg. It is a widely used measure in science, engineering and commerce worldwide, and is often simply called a kilo colloquiall ...
, because the kilogram was originally defined in 1795 as the mass of one cubic decimetre of water at the temperature of melting ice (). Subsequent redefinitions of the metre and kilogram mean that this relationship is no longer exact.


Definition

A litre is a cubic
decimetre The decimetre (symbol dm) or decimeter (American English) is a unit of length in the International System of Units (SI), equal to one tenth of a metre, ten centimetres, 100 millimetres or 3.937 inches. The common non-SI metric unit of volume ...
, which is the volume of a cube 10 centimetres × 10 centimetres × 10 centimetres (1 L ≡ 1 dm3 ≡ 1000 cm3). Hence 1 L ≡ 0.001  m3 ≡ 1000  cm3; and 1 m3 (i.e. a cubic metre, which is the SI unit for volume) is exactly 1000 L. From 1901 to 1964, the litre was defined as the volume of one kilogram of pure water at maximum density (+4 °C) and standard pressure. The kilogram was in turn specified as the mass of the
International Prototype of the Kilogram The International Prototype of the Kilogram (referred to by metrologists as the IPK or Le Grand K; sometimes called the '' ur-kilogram,'' or ''urkilogram,'' particularly by German-language authors writing in English) is an object that was used t ...
(a specific platinum/iridium cylinder) and was intended to be of the same mass as the 1 litre of water referred to above. It was subsequently discovered that the cylinder was around 28 parts per million too large and thus, during this time, a litre was about . Additionally, the mass–volume relationship of water (as with any fluid) depends on temperature, pressure, purity and isotopic uniformity. In 1964, the definition relating the litre to mass was superseded by the current one. Although the litre is not an SI unit, it is accepted by the CGPM (the standards body that defines the SI) for use with the SI. CGPM defines the litre and its acceptable symbols. A litre is equal in volume to the millistere, an obsolete non-SI
metric Metric or metrical may refer to: * Metric system, an internationally adopted decimal system of measurement * An adjective indicating relation to measurement in general, or a noun describing a specific type of measurement Mathematics In mathema ...
unit formerly customarily used for
dry measure Dry measures are units of volume to measure bulk commodities that are not fluids and that were typically shipped and sold in standardized containers such as barrels. They have largely been replaced by the units used for measuring volumes in the me ...
.


Explanation

Litres are most commonly used for items (such as
fluid In physics, a fluid is a liquid, gas, or other material that continuously deforms (''flows'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear ...
s and solids that can be poured) which are measured by the capacity or size of their container, whereas cubic metres (and derived units) are most commonly used for items measured either by their dimensions or their displacements. The litre is often also used in some calculated measurements, such as density (kg/L), allowing an easy comparison with the density of water. One litre of water has a
mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different eleme ...
of almost exactly one
kilogram The kilogram (also kilogramme) is the unit of mass in the International System of Units (SI), having the unit symbol kg. It is a widely used measure in science, engineering and commerce worldwide, and is often simply called a kilo colloquiall ...
when measured at its maximal density, which occurs at about 4 °C. It follows, therefore, that 1000th of a litre, known as one millilitre (1 mL), of water has a mass of about 1 g; 1000 litres of water has a mass of about 1000 kg (1 
tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000  kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton (United States ...
or megagram). This relationship holds because the gram was originally defined as the mass of 1 mL of water; however, this definition was abandoned in 1799 because the density of water changes with temperature and, very slightly, with pressure. It is now known that the density of water also depends on the isotopic ratios of the oxygen and hydrogen atoms in a particular sample. Modern measurements of
Vienna Standard Mean Ocean Water Vienna Standard Mean Ocean Water (VSMOW) is an isotopic standard for water. Despite the name, VSMOW is pure water with no salt or other chemicals found in the oceans. The VSMOW standard was promulgated by the International Atomic Energy Agency ( ...
, which is pure distilled water with an isotopic composition representative of the average of the world's oceans, show that it has a density of at its point of maximum density (3.984 °C) under one standard atmosphere (101.325 
kPa KPA may refer to: * Keele Postgraduate Association, Keele University, UK, formerly Keele Research Association (KRA) * Kensington (Olympia) station, London, England, National Rail station code * Kenya Ports Authority * ''Kiln phosphoric acid'', a ...
) of pressure.


SI prefixes applied to the litre

The litre, though not an official SI unit, may be used with
SI prefix The International System of Units, known by the international abbreviation SI in all languages and sometimes pleonastically as the SI system, is the modern form of the metric system and the world's most widely used system of measurement. E ...
es. The most commonly used derived unit is the millilitre, defined as one-thousandth of a litre, and also often referred to by the SI derived unit name "cubic centimetre". It is a commonly used measure, especially in medicine, cooking and automotive engineering. Other units may be found in the table below, where the more often used terms are in bold. However, some authorities advise against some of them; for example, in the United States,
NIST The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sc ...
advocates using the millilitre or litre instead of the centilitre. There are two international standard symbols for the litre: L and l. In the United States the former is preferred because of the risk that (in some fonts) the letter and the digit may be confused.


Non-metric conversions

See also
Imperial unit The imperial system of units, imperial system or imperial units (also known as British Imperial or Exchequer Standards of 1826) is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed thr ...
s and
US customary units United States customary units form a system of measurement units commonly used in the United States and U.S. territories since being standardized and adopted in 1832. The United States customary system (USCS or USC) developed from English unit ...
.


Rough conversions

One litre is slightly larger than a US liquid quart and slightly less than an imperial quart or one US dry quart. A
mnemonic A mnemonic ( ) device, or memory device, is any learning technique that aids information retention or retrieval (remembering) in the human memory for better understanding. Mnemonics make use of elaborative encoding, retrieval cues, and imager ...
for its volume relative to an imperial pint is "a litre of water's a pint and three-quarters"; this is very close, as a litre is actually 1.75975399 pints. A cubic foot has an exact volume of 28.316846592 litres.


Symbol

Originally, the only symbol for the litre was l (lowercase letter L), following the SI convention that only those unit symbols that abbreviate the name of a person start with a capital letter. In many English-speaking countries, however, the most common shape of a handwritten
Arabic digit Arabic numerals are the ten numerical digits: , , , , , , , , and . They are the most commonly used symbols to write decimal numbers. They are also used for writing numbers in other systems such as octal, and for writing identifiers such as ...
1 is just a vertical stroke; that is, it lacks the upstroke added in many other cultures. Therefore, the digit "1" may easily be confused with the letter "l". In some computer typefaces, the two characters are barely distinguishable. As a result, L (uppercase letter L) was adopted by the
CIPM The General Conference on Weights and Measures (GCWM; french: Conférence générale des poids et mesures, CGPM) is the supreme authority of the International Bureau of Weights and Measures (BIPM), the intergovernmental organization established ...
as an alternative symbol for litre in 1979. The
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territo ...
National Institute of Standards and Technology The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sc ...
now recommends the use of the uppercase letter L, a practice that is also widely followed in
Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world ...
and Australia. In these countries, the symbol L is also used with prefixes, as in mL and μL, instead of the traditional ml and μl used in Europe. In the UK and
Ireland Ireland ( ; ga, Éire ; Ulster-Scots: ) is an island in the North Atlantic Ocean, in north-western Europe. It is separated from Great Britain to its east by the North Channel, the Irish Sea, and St George's Channel. Ireland is the s ...
, as well as the rest of Europe, lowercase ''l'' is used with prefixes, though whole litres are often written in full (so, "750 ml" on a wine bottle, but often "1 litre" on a juice carton). In 1990, the
International Committee for Weights and Measures The General Conference on Weights and Measures (GCWM; french: Conférence générale des poids et mesures, CGPM) is the supreme authority of the International Bureau of Weights and Measures (BIPM), the intergovernmental organization established ...
stated that it was too early to choose a single symbol for the litre.


Script l

Prior to 1979, the symbol came into common use in some countries; for example, it was recommended by South African Bureau of Standards publication M33 and Canada in the 1970s. This symbol can still be encountered occasionally in some English-speaking and European countries like Germany, and its use is ubiquitous in Japan and South Korea. Fonts covering the
CJK characters In internationalization, CJK characters is a collective term for the Chinese, Japanese, and Korean languages, all of which include Chinese characters and derivatives in their writing systems, sometimes paired with other scripts. Collectively, th ...
usually include not only the script small but also four precomposed characters: for the microlitre, millilitre, decilitre and kilolitre to allow correct rendering for vertically written scripts. These have
Unicode Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, whi ...
equivalents for compatibility, which are not recommended for use with new documents: * * * * *


History

The first name of the litre was "cadil"; standards are shown at the
Musée des Arts et Métiers The Musée des Arts et Métiers () ( French for Museum of Arts and Crafts) is an industrial design museum in Paris that houses the collection of the Conservatoire national des arts et métiers, which was founded in 1794 as a repository for the ...
in Paris. The litre was introduced in France in 1795 as one of the new "republican units of measurement" and defined as one cubic decimetre. English translation: "''Litre'': unit of capacity for both liquids and solids which will be equivalent to a cube of ith sidesone tenth of a metre." One litre of liquid water has a
mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different eleme ...
of almost exactly one
kilogram The kilogram (also kilogramme) is the unit of mass in the International System of Units (SI), having the unit symbol kg. It is a widely used measure in science, engineering and commerce worldwide, and is often simply called a kilo colloquiall ...
, due to the gram being defined in 1795 as one cubic centimetre of water at the temperature of melting ice. English translation: "''Gramme'': the absolute weight of a volume of pure water equal to the cube of the hundredth part of the metre, at the temperature of melting ice." The original decimetre length was 44.344 ''lignes'', which was revised in 1798 to 44.3296 ''lignes''. This made the original litre of today's cubic decimetre. It was against this litre that the kilogram was constructed. In 1879, the
CIPM The General Conference on Weights and Measures (GCWM; french: Conférence générale des poids et mesures, CGPM) is the supreme authority of the International Bureau of Weights and Measures (BIPM), the intergovernmental organization established ...
adopted the definition of the litre, with the symbol l (lowercase letter L). In 1901, at the 3rd CGPM conference, the litre was redefined as the space occupied by 1 kg of pure
water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
at the temperature of its maximum density (3.98 °C) under a pressure of 1  atm. This made the litre equal to about (earlier reference works usually put it at ). In 1964, at the 12th CGPM conference, the original definition was reverted to, and thus the litre was once again defined in exact relation to the metre, as another name for the cubic decimetre, that is, exactly 1 dm3. In 1979, at the 16th CGPM conference, the alternative symbol L (uppercase letter L) was adopted. It also expressed a preference that in the future only one of these two symbols should be retained, but in 1990 said it was still too early to do so.


Everyday usage

In spoken English, the symbol "mL" (for millilitre) can be pronounced as "mil". This can potentially cause confusion with some other measurement words such as: # "mm" for
millimetre file:EM Spectrum Properties edit.svg, 330px, Different lengths as in respect to the electromagnetic spectrum, measured by the metre and its derived scales. The microwave is between 1 meter to 1 millimeter. The millimetre (American and British Eng ...
, a unit of length equal to one-thousandth of a metre # "mil" for thousandth of an ''inch'' # "'' mil''", a Scandinavian unit of length equal to 10 kilometres # " mil", unit of angular measurement The abbreviation "cc" (for
cubic centimetre A cubic centimetre (or cubic centimeter in US English) (SI unit symbol: cm3; non-SI abbreviations: cc and ccm) is a commonly used unit of volume that corresponds to the volume of a cube that measures 1 cm × 1 cm × 1 cm. One cu ...
, equal to a millilitre or mL) is a unit of the cgs system, which preceded the
MKS system The MKS system of units is a physical system of measurement that uses the metre, kilogram, and second (MKS) as base units. It forms the base of the International System of Units (SI), though SI has since been redefined by different fundamental co ...
, which later evolved into the SI system. The abbreviation "cc" is still commonly used in many fields, including medical dosage and sizing for combustion engine
displacement Displacement may refer to: Physical sciences Mathematics and Physics * Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object). The actual path ...
. The microlitre (μL) has been known in the past as the
lambda Lambda (}, ''lám(b)da'') is the 11th letter of the Greek alphabet, representing the voiced alveolar lateral approximant . In the system of Greek numerals, lambda has a value of 30. Lambda is derived from the Phoenician Lamed . Lambda gave ris ...
(λ), but this usage is now discouraged. In the medical field the microlitre is sometimes abbreviated as mcL on test results. In the SI system, apart from prefixes for powers of 1000, use of the "centi" (10−2), "deci" (10−1), "deca" (10+1) and "hecto" (10+2) prefixes with litres is common. For example, in many European countries, the hectolitre is the typical unit for production and export volumes of
beverages A drink or beverage is a liquid intended for human consumption. In addition to their basic function of satisfying thirst, drinks play important roles in human culture. Common types of drinks include plain drinking water, milk, juice, smoothies a ...
(milk, beer, soft drinks, wine, etc.) and for measuring the size of the catch and quotas for fishing boats; decilitres are common in
Croatia , image_flag = Flag of Croatia.svg , image_coat = Coat of arms of Croatia.svg , anthem = "Lijepa naša domovino"("Our Beautiful Homeland") , image_map = , map_caption = , capit ...
,
Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...
and
Scandinavia Scandinavia; Sámi languages: /. ( ) is a subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, Norway, and Swed ...
and often found in cookbooks, and restaurant and café menus; centilitres indicate the capacity of drinking glasses and of small bottles. In colloquial
Dutch Dutch commonly refers to: * Something of, from, or related to the Netherlands * Dutch people () * Dutch language () Dutch may also refer to: Places * Dutch, West Virginia, a community in the United States * Pennsylvania Dutch Country People ...
in
Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to the ...
, a "" and a "" (literally "twenty-fiver" and "thirty-threer") are the common beer glasses, the corresponding bottles mention 25 cL and 33 cL. Bottles may also be 75 cL or half size at 37.5 cL for "artisanal" brews or 70 cL for wines or spirits. Cans come in 25 cL, 33 cL and 50 cL. Similarly, alcohol shots are often marked in cL in restaurant menus, typically . In countries where the metric system was adopted as the official measuring system after the SI standard was established, common usage eschews prefixes that are not powers of 1000. For example, in
Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world ...
, Australia, and
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island country ...
, consumer beverages are labelled almost exclusively using litres and millilitres. Hectolitres sometimes appear in industry, but centilitres and decilitres are rarely, if ever, used. An exception is in pathology, where for instance
blood lead level Blood lead level (BLL), is a measure of the amount of lead in the blood. Lead is a toxic heavy metal and can cause neurological damage, especially among children, at any detectable level. High lead levels cause decreased vitamin D and haemoglob ...
and
blood sugar level Glycaemia, also known as blood sugar level, blood sugar concentration, or blood glucose level is the measure of glucose concentrated in the blood of humans or other animals. Approximately 4 grams of glucose, a simple sugar, is present in the bl ...
may be measured in micrograms/milligrams per decilitre. Larger volumes are usually given in cubic metres (equivalent to 1 kL), or thousands or millions of cubic metres. Although kilolitres, megalitres, and gigalitres are commonly used for measuring water consumption, reservoir capacities and river flows, for larger volumes of fluids, such as annual consumption of tap water, lorry (truck) tanks, or swimming pools, the
cubic metre The cubic metre (in Commonwealth English and international spelling as used by the International Bureau of Weights and Measures) or cubic meter (in American English) is the unit of volume in the International System of Units (SI). Its symbol is ...
is the general unit. It is also generally for all volumes of a non-liquid nature.


See also

*
Acre-foot The acre-foot is a non- SI unit of volume equal to about commonly used in the United States in reference to large-scale water resources, such as reservoirs, aqueducts, canals, sewer flow capacity, irrigation water, and river flows. An acre-f ...
* Claude Émile Jean-Baptiste Litre * Integrated nanolitre system


Notes


References


Bibliography

* * Bureau International des Poids et Mesures. (2006)
"The International System of Units (SI)"
(on-line browser):

(Non-SI units accepted for use with the International System). Retrieved 2008-08-24 * * National Institute of Standards and Technology. (December 2003)

(web site): ** ttp://physics.nist.gov/cuu/Units/units.html ''Note on SI units'' Retrieved 2008-08-24. *
''Recommending uppercase letter L''
Retrieved 2008-08-24. * Taylor, B.N. and Thompson, A. (Eds.). (2008a)
''The International System of Units (SI)''
. United States version of the English text of the eighth edition (2006) of the International Bureau of Weights and Measures publication ''Le Système International d' Unités (SI)'' (Special Publication 330). Gaithersburg, MD: National Institute of Standards and Technology. Retrieved 2008-08-18. * Taylor, B.N. and Thompson, A. (2008b)
''Guide for the Use of the International System of Units''
(Special Publication 811). Gaithersburg, MD: National Institute of Standards and Technology. Retrieved 2008-08-23. * Turner, J. (Deputy Director of the National Institute of Standards and Technology). (16 May 2008
"Interpretation of the International System of Units (the Metric System of Measurement) for the United States"
''Federal Register'' Vol. 73, No. 96, p. 28432-3. * UK National Physical Laboratory
Non-SI Units
{{SI units Alcohol measurement Non-SI metric units Units of volume Cooking weights and measures