"use. Unit prefix A unit prefix is a specifier or mnemonic that is prepended to units of measurement to indicate multiples or fractions of the units. Units of various sizes are commonly formed by the use of such prefixes. The prefixes of the metric system, such as ""kilo"" and ""milli"", represent multiplication by powers of ten. In information technology it is common to use binary prefixes, which are based on powers of two. Historically, many prefixes have been used or proposed by various sources, but only a narrow set has been recognised by standards organisations. The prefixes of the metric"
"Metric prefix A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or fraction of the unit. While all metric prefixes in common use today are decadic, historically there have been a number of binary metric prefixes as well. Each prefix has a unique symbol that is prepended to the unit symbol. The prefix ""kilo-"", for example, may be added to ""gram"" to indicate ""multiplication"" by one thousand: one kilogram is equal to one thousand grams. The prefix ""milli-"", likewise, may be added to ""metre"" to indicate ""division"" by one thousand; one"
"millimetre is equal to one thousandth of a metre. Decimal multiplicative prefixes have been a feature of all forms of the metric system, with six dating back to the system's introduction in the 1790s. Metric prefixes have even been prepended to non-metric units. The SI prefixes are standardized for use in the International System of Units (SI) by the International Bureau of Weights and Measures (BIPM) in resolutions dating from 1960 to 1991. Since 2009, they have formed part of the International System of Quantities. The BIPM specifies twenty prefixes for the International System of Units (SI). Each prefix name"
"meaning 1000 and respectively, were commonly used in the electronics industry before World War II. Along with ""giga-"" or G-, meaning , they are now known as SI prefixes after the International System of Units (SI), introduced in 1960 to formalize aspects of the metric system. The International System of Units does not define units for digital information but notes that the SI prefixes may be applied outside the contexts where base units or derived units would be used. But as computer main memory in a binary-addressed system is manufactured in sizes that were easily expressed as multiples of 1024,"
"precede a basic unit of measure to indicate a decadic multiple and fraction of a unit. Each prefix has a unique symbol that is prepended to the unit symbol. Some of the prefixes date back to the introduction of the metric system in the 1790s, but new prefixes have been added, and some have been revised. The International Bureau of Weights and Measures has standardised twenty metric prefixes in resolutions dating from 1960 to 1991 for use with the International System of Units (SI). Although formerly in use, the SI disallows combining prefixes; the microkilogram or centimillimetre, for example, are"
"Binary prefix A binary prefix is a unit prefix for multiples of units in data processing, data transmission, and digital information, notably the bit and the byte, to indicate multiplication by a power of 2. The computer industry has historically used the units ""kilobyte"", ""megabyte"", and ""gigabyte"", and the corresponding symbols KB, MB, and GB, in at least two slightly different measurement systems. In citations of main memory (RAM) capacity, ""gigabyte"" customarily means bytes. As this is a power of 1024, and 1024 is a power of two (2), this usage is referred to as a binary measurement. In most"
"are one thousand millimetres to the metre and one thousand metres to the kilometre. The prefixes are never combined, so for example a millionth of a metre is a ""micrometre"", not a millimillimetre. Multiples of the kilogram are named as if the gram were the base unit, so a millionth of a kilogram is a ""milligram"", not a microkilogram. When prefixes are used to form multiples and submultiples of SI base and derived units, the resulting units are no longer coherent. The BIPM specifies twenty prefixes for the International System of Units (SI): Many non-SI units continue to be used"
"Mega- Mega is a unit prefix in metric systems of units denoting a factor of one million (10 or ). It has the unit symbol M. It was confirmed for use in the International System of Units (SI) in 1960. ""Mega"" comes from . When units occur in exponentiation, such as in square and cubic forms, any multiples-prefix is considered part of the unit, and thus included in the exponentiation. In some fields of computing, ""mega"" may sometimes denote 1,048,576 (2) of information units, for example, a megabyte, a megaword, but denotes (10) units of other quantities, for example, transfer"
"rates: = . The prefix ""mebi-"" has been suggested as a prefix for 2 to avoid ambiguity. Mega- Mega is a unit prefix in metric systems of units denoting a factor of one million (10 or ). It has the unit symbol M. It was confirmed for use in the International System of Units (SI) in 1960. ""Mega"" comes from . When units occur in exponentiation, such as in square and cubic forms, any multiples-prefix is considered part of the unit, and thus included in the exponentiation. In some fields of computing, ""mega"" may sometimes denote 1,048,576 (2) of information"
"decibel. Metric prefixes rarely appear with imperial or US units except in some special cases (e.g., microinch, kilofoot, kilopound or 'kip'). They are also used with other specialized units used in particular fields (e.g., megaelectronvolt, gigaparsec, millibarn). They are also occasionally used with currency units (e.g., gigadollar), mainly by people who are familiar with the prefixes from scientific usage. In geology and paleontology, the year, with symbol a (from the Latin ""annus""), is commonly used with metric prefixes: ka, Ma, and Ga. When an SI prefix is affixed to a root word, the prefix carries the stress, while the root"
"Micro- Micro- (Greek letter μ or legacy micro symbol µ) is a unit prefix in the metric system denoting a factor of 10 (one millionth). Confirmed in 1960, the prefix comes from the Greek (""""), meaning ""small"". The symbol for the prefix comes from the Greek letter μ (mu). It is the only SI prefix which uses a character not from the Latin alphabet. ""mc"" is commonly used as a prefix when the character ""μ"" is not available; for example, ""mcg"" commonly denotes a microgram. Also the letter u instead of μ is allowed by one of the ISO documents."
"Zetta- Zetta is a decimal unit prefix in the metric system denoting a factor of 10 or . The prefix was added as an SI prefix to the International System of Units (SI) in 1991 and has the symbol Z. Zetta is evocative of the Latin numeral , meaning ""seven"". Therefore it was used to denote the seventh power of 1000. A prefix of the same value, ""hepta"", was informally introduced a few years before the promulgation of zetta. It was formed from the Greek (), also meaning ""seven"". ""Hepta"" never received official sanction and is obsolete. Zeta (), although"
"the SI prefix and ""bi"" from binary. The first letter of each such prefix is therefore identical to the corresponding SI prefixes, except for ""K"", which is used interchangeably with ""k"", whereas in SI, only the lower-case k represents 1000. The IEEE decided that their standards would use the prefixes ""kilo"", etc. with their metric definitions, but allowed the binary definitions to be used in an interim period as long as such usage was explicitly pointed out on a case-by-case basis. In January 1999, the IEC published the first international standard (IEC 60027-2 Amendment 2) with the new prefixes, extended"
"1024. To address this conflict, a new set of binary prefixes has been introduced, which is based on powers of 2. Therefore, 1024 bytes are defined as one kibibyte (1 KiB). When units occur in exponentiation, such as in square and cubic forms, any multiplier prefix is considered part of the unit, and thus included in the exponentiation. Kilo- Kilo is a decimal unit prefix in the metric system denoting multiplication by one thousand (10). It is used in the International System of Units where it has the unit symbol k, in lower case. The prefix ""kilo"" is derived from"
"""symbol"" for any SI unit kilometres per hour are always written ""km/h"" regardless of local script. Both the symbols used for the prefix of a metric unit and the unit itself are case-sensitive. Prefixes representing multipliers up to and including ""1000"" (k) are written in lower-case letters and those above 1000 are written in upper-case letters. This is particularly important for some units of measure for example a hearing aid requires about 1 mW (milliwatt) while the central air conditioning unit in a large office block might require 1 MW (megawatt). The symbol for the unit name itself is written"
"scale of nanometres"". See nanoscopic scale. Nano- Nano- (symbol n) is a unit prefix meaning ""one billionth"". Used primarily with the metric system, this prefix denotes a factor of 10 or . It is frequently encountered in science and electronics for prefixing units of time and length. Examples: The prefix derives from the Greek (Latin ""nanus""), meaning ""dwarf"". The General Conference on Weights and Measures (CGPM) officially endorsed the usage of ""nano"" as a standard prefix in 1960. When used as a prefix for something other than a unit of measure (as for example in words like ""nanoscience""), nano refers"
"other contexts, the industry uses the multipliers ""kilo"", ""mega"", ""giga"", etc., in a manner consistent with their meaning in the International System of Units (SI), namely as powers of 1000. For example, a 500 gigabyte hard disk holds bytes, and a 1 Gbit/s (gigabit per second) Ethernet connection transfers data at bit/s. In contrast with the ""binary prefix"" usage, this use is described as a ""decimal prefix"", as 1000 is a power of 10 (10). The use of the same unit prefixes with two different meanings has caused confusion. Starting around 1998, the International Electrotechnical Commission (IEC) and several other"
"Nano- Nano- (symbol n) is a unit prefix meaning ""one billionth"". Used primarily with the metric system, this prefix denotes a factor of 10 or . It is frequently encountered in science and electronics for prefixing units of time and length. Examples: The prefix derives from the Greek (Latin ""nanus""), meaning ""dwarf"". The General Conference on Weights and Measures (CGPM) officially endorsed the usage of ""nano"" as a standard prefix in 1960. When used as a prefix for something other than a unit of measure (as for example in words like ""nanoscience""), nano refers to nanotechnology, or means ""on a"
"Giga- Giga ( or ) is a unit prefix in the metric system denoting a factor of a (short-form) billion (10 or ). It has the symbol G. ""Giga"" is derived from the Greek word , meaning ""giant"". The ""Oxford English Dictionary"" reports the earliest written use of ""giga"" in this sense to be in the Reports of the IUPAC 14th Conference in 1947: ""The following prefixes to abbreviations for the names of units should be used: G giga 10×"". When referring to information units in computing, such as gigabyte, giga may sometimes mean (2), although such use is inconsistent,"
"this convention: the prefixes ""nano-"" and ""micro-"", for example have Greek roots. During the 19th century the prefix ""myria-"", derived from the Greek word μύριοι (""mýrioi""), was used as a multiplier for . When applying prefixes to derived units of area and volume that are expressed in terms of units of length squared or cubed, the square and cube operators are applied to the unit of length including the prefix, as illustrated below. Prefixes are not usually used to indicate multiples of a second greater than 1; the non-SI units of minute, hour and day are used instead. On the"
"architectures. However, most standards bodies have deprecated this usage in favor of a set of binary prefixes, in which this quantity is designated by the unit mebibyte (MiB). Less common is a convention that used the megabyte to mean 1000×1024 () bytes. The megabyte is commonly used to measure either 1000 bytes or 1024 bytes. The interpretation of using base 1024 originated as a compromise technical jargon for the byte multiples that needed to be expressed by the powers of 2 but lacked a convenient name. As 1024 (2) approximates 1000 (10), roughly corresponding to the SI prefix kilo-, it"
"others don't), and in physical sciences academia, ""μg"" remains the sole official abbreviation. In medical data exchange according to the Health Level 7 (HL7) standard, the μ can be replaced by u as well. Micro- Micro- (Greek letter μ or legacy micro symbol µ) is a unit prefix in the metric system denoting a factor of 10 (one millionth). Confirmed in 1960, the prefix comes from the Greek (""""), meaning ""small"". The symbol for the prefix comes from the Greek letter μ (mu). It is the only SI prefix which uses a character not from the Latin alphabet. ""mc"" is"
"where 'MMbbl' is the symbol for 'millions of barrels'. This usage of the capital letter M for 'thousand' is from Roman numerals, in which M means 1,000. In some fields of information technology, it has been common to designate non-decimal multiples based on powers of 1024, rather than 1000, for some SI prefixes (kilo, mega, giga), contrary to the definitions in the International System of Units (SI). This practice was once sanctioned by some industry associations, including JEDEC. The International Electrotechnical Commission (IEC) standardized the system of binary prefixes (kibi, mebi, gibi, etc.) for this purpose. Metric prefix A metric"
"given unit has often arisen by convenience of use and historical developments. Unit prefixes that are much larger or smaller than encountered in practice are seldom used, albeit valid combinations. In most contexts only a few, the most common, combinations are established. For example, prefixes for multiples greater than one thousand are rarely applied to the gram or metre. Some prefixes used in older versions of the metric system are no longer used. The prefixes ""myria-"", (from the Greek μύριοι, ""mýrioi""), ""double-"" and ""demi-"", denoting a factors of , 2 and respectively, were parts of the original metric system adopted"
"of Units (SI) as a multiplier of 10. The binary prefixes have been accepted by all major standards organizations and are part of the International System of Quantities. Many Linux distributions use the unit, but it is not widely acknowledged within the industry or media. One thousand twenty-four mebibytes (1024 MiB) is equal to one gibibyte (1 GiB). The prefix ""mebi"" is a binary prefix derived from the words mega and binary, indicating its origin in the closeness in value to the SI prefix ""mega"". One mebibyte (MiB) is 2, i.e. 1024 × 1024 bytes, or . Despite its official"
"and milligauss). Metric prefixes may also be used with non-metric units. The choice of prefixes with a given unit is usually dictated by convenience of use. Unit prefixes for amounts that are much larger or smaller than those actually encountered are seldom used. In use, the kilogram, gram, milligram, microgram, and smaller are fairly common. However, megagram (and gigagram, teragram, etc.) are rarely used; tonnes (and kilotonnes, megatonnes, etc. – although these units generally are not used as a measure of mass ""per se"", but rather TNT energy equivalent of a mass) or scientific notation are used instead. Megagram is"
"first used to mean 1024. Because both the SI and ""binary"" meanings of kilo, mega, etc., are based on powers of 1000 or 1024 rather than simple multiples, the difference between 1M ""binary"" and 1M ""decimal"" is proportionally larger than that between 1K ""binary"" and 1k ""decimal,"" and so on up the scale. The relative difference between the values in the binary and decimal interpretations increases, when using the SI prefixes as the base, from 2.4% for kilo to nearly 21% for the yotta prefix. In the early days of computers (roughly, prior to the advent of personal computers) there"
"true. The decimal SI prefixes ""kilo"", ""mega"", ""giga"", ""tera"", etc., are powers of 10 = 1000. The binary prefixes ""kibi"", ""mebi"", ""gibi"", ""tebi"", etc. respectively refer to the corresponding power of 2 = 1024. In casual usage, when 1024 is a close enough approximation of 1000, the two corresponding prefixes are equivalent. Note: this page mixes between two kinds of entropies: These two definitions are not entirely equivalent, see Entropy in thermodynamics and information theory. For comparison, the Avogadro constant is entities per mole, based upon the number of atoms in 12 grams of carbon-12 isotope. In 2012, some hard"
"1000 grams, and one kilowatt is 1000 watts. Each unit and each prefix in the metric systems has been allocated a unique symbol by the CGPM. Unlike abbreviations which are a contraction of the local word for the unit in question, and which can therefore differ from one language to another, SI symbols are a form of standardised mathematical notation to represent the units and are the same in any language (compare chemical symbols). There are certain circumstances where abbreviations (as opposed to the SI symbols) are used, particularly where safety is concerned. One such instance is the use of"
"The prefixes hecto, deca, deci, and centi are commonly used for everyday purposes, and the centimetre (cm) is especially common. However, some modern building codes require that the millimetre be used in preference to the centimetre, because ""use of centimetres leads to extensive usage of decimal points and confusion"". Prefixes may not be used in combination. This also applies to mass, for which the SI base unit (kilogram) already contains a prefix. For example, milligram (mg) is used instead of microkilogram (μkg). In the arithmetic of measurements having units, the units are treated as multiplicative factors to values. If they"
"occasionally used to disambiguate the metric tonne from the various non-metric tons. An exception is pollution emission rates, which are typically on the order of Tg/yr. Sometimes, only one element or compound is denoted for an emission, such as Tg C/yr or Tg N/yr. Alone among SI units, the base unit of mass, the kilogram, already includes a prefix. The prefixes consequently do not indicate corresponding multipliers of the base unit in the case of mass; for example, a megagram is kg, whereas ""mega-"" indicates a multiplier of . The litre (equal to a cubic decimetre), millilitre (equal to a"
"and derived units may be used to express other derived units. For example, the SI unit of force is the newton (N), the SI unit of pressure is the pascal (Pa)—and the pascal can be defined as one newton per square metre (N/m). Prefixes are added to unit names to produce multiples and sub-multiples of the original unit. All of these are integer powers of ten, and above a hundred or below a hundredth all are integer powers of a thousand. For example, ""kilo-"" denotes a multiple of a thousand and ""milli-"" denotes a multiple of a thousandth, so there"
"Gbit). These prefixes are more often used for multiples of bytes, as in kilobyte (1 kB = 8000 bit), megabyte (1 MB = ), and gigabyte (1 GB = ). However, for technical reasons, the capacities of computer memories and some storage units are often multiples of some large power of two, such as 2 = bytes. To avoid such unwieldy numbers, people have often repurposed the SI prefixes to mean the nearest power of two, e.g., using the prefix ""kilo"" for 2 = 1024, ""mega"" for 2 = , and ""giga"" for 2 = , and so on. For"