Non-SI metric units

thumb|upright|One-litre beer mugs () at the Oktoberfest in Germany

thumb|Image comparing the hectare (the small blue area at lower left) to other units. The entire yellow square is one square mile. 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 and thus one hectare is about . thumb|St. Enda's GAA ground, in Omagh. The playing field used in [[Gaelic football and hurling is a little over a hectare in size.]] In 1795, when the metric syste

The tonne ( or ; symbol: t) is a unit of mass equal to 1,000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the short ton and the long ton. One tonne is equivalent to approximately 2,204.6 pounds, 1.102 short tons, and 0.984 long tons. The exact corresponding SI unit is the megagram (symbol Mg), a less common way to express the same mass.

The calorie is a unit of energy that originated from the caloric theory of heat. The small calorie or gram calorie is defined as the amount of heat needed to raise the temperature of one milliliter of water by one degree Celsius (or one kelvin). In the US, "large calorie" is also used to mean kilocalorie (1 kcal = 1000 cal) .

The angstrom (; ) is a unit of length equal to m; that is, one ten-billionth of a metre, a hundred-millionth of a centimetre, 0.1 nanometre, or 100 picometres. The unit is named after the Swedish physicist Anders Jonas Ångström (1814–1874). It was originally spelled with Swedish letters, as Ångström and later as ångström (). The latter spelling is still listed in some dictionaries, but is now rare in English texts. Some popular US dictionaries list only the spelling angstrom.

non-SI unit of pressure

unit of speed

thumb|Illustration of the relationship between optical power in dioptres and focal length in metres. A dioptre (British spelling) or ' (American spelling), symbol dpt or D', is a unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, . It is normally used to express the optical power of a lens or curved mirror, which is a physical quantity equal to the reciprocal of the focal length, expressed in metres. For example, a 3-dioptre lens brings parallel rays of light to focus at metre. A flat window has an optical power of zero dioptres, as it does not cause l

A kilowatt-hour (unit symbol: kW⋅h or kW h; commonly written as kWh) is a non-SI unit of energy equal to 3.6 megajoules (MJ) in SI units, which is the energy delivered by one kilowatt of power for one hour. Kilowatt-hours are a common billing unit for electrical energy supplied by electric utilities. Metric prefixes are used for multiples and submultiples of the basic unit, the watt-hour (3.6 kJ).

non-SI unit of radioactivity

In trigonometry, the gradianalso known as the gon (), grad, or gradeis a unit of measurement of an angle, defined as one-hundredth of the right angle; in other words, 100 gradians is equal to 90 degrees. It is equivalent to of a turn, of a degree, or of a radian. Measuring angles in gradians (gons) is said to employ the centesimal system of angular measurement, initiated as part of metrication and decimalisation efforts.

legacy unit of measurement for the kerma of X-rays and gamma rays up to 3 MeV; equals 0.258 mC/kg

The kilogram-force (kgf or kgF), or kilopond (kp, from ), is a non-standard gravitational metric unit of force. It is not accepted for use with the International System of Units (SI) and is deprecated for most uses. The kilogram-force is equal to the magnitude of the force exerted on one kilogram of mass in a gravitational field (standard gravity, a conventional value approximating the average magnitude of gravity on Earth). That is, it is the weight of a kilogram under standard gravity. One kilogram-force is defined as . Similarly, a gram-force is , and a milligram-force is .

The quintal or centner is a historical unit of mass in many countries that is usually defined as 100 base units, such as pounds or kilograms. It is a traditional unit of weight in France, Portugal, and Spain and their former colonies. It is commonly used for grain prices in wholesale markets in Ethiopia, Eritrea and India, where 1 quintal = .

unit for cross-sectional

An ampere-hour or amp-hour (symbol: A⋅h or A h, often simplified as Ah) is a unit of electric charge, recommended for use in batteries and electrolytic devices. It has dimensions of electric current multiplied by time and corresponds to the charge transferred by a steady current of one ampere flowing for one hour (3,600 seconds). Thus 1A⋅h equals 3600 A⋅s or 3.6kC (kilocoulombs).

The debye ( , ; symbol: D) is a CGS unit (a non-SI metric unit) of electric dipole moment named in honour of the physicist Peter J. W. Debye. Likely the earliest recommendation for the Debye as a unit was in the Physikalisch-chemisches Taschenbuch (physical chemistry handbook) written by Carl Drucker and Erich Proskauer in early 1932. It is defined as statcoulomb-centimetres. Historically the debye was defined as the dipole moment resulting from two charges of opposite sign but an equal magnitude of 10−10 statcoulomb (generally called e.s.u. (electrostatic unit) in older scienti

non-SI unit measuring absorbed dose of ionizing radiation

The torr (symbol: Torr) is a unit of pressure based on an absolute scale, defined as exactly of a standard atmosphere (101325 Pa). Thus one torr is exactly (≈ ).

unit of measurement; equals 1 centisievert

In oceanography, the sverdrup (symbol: Sv) is a non-SI metric unit of volumetric flow rate, with equal to , or equivalently 1 cubic hectometer per second (symbol: hm3/s or hm3⋅s−1). It is used almost exclusively in oceanography to measure the volumetric rate of transport of ocean currents. It is named after Harald Sverdrup.

thumb|250px|A laboratory ultracentrifuge.

thumb|280px|The stere as a cubic metre of stacked firewood The stere or stère (st) is a unit of volume in the original metric system equal to one cubic metre. The stere is typically used for measuring large quantities of firewood or other cut wood, while the cubic meter is used for uncut wood. The name was coined from the Greek στερεός stereós, "solid", in 1795 in France as a metric analogue to the cord. The unit was introduced to remove regional disparities of this former unit, for which the length could vary greatly from 6 to 13.5 m. It is not part of the modern metric system (SI) and is no

The jansky (symbol Jy, plural janskys) is a non-SI unit of spectral flux density, or spectral irradiance, used especially in radio astronomy. It is equivalent to 10−26 watts per square metre per hertz.

system of units based on the three base quantities length, time and force with base units metre, second and kilopond

unit of luminance; 10000/π candelas per square metre

obsolete unit of pressure

Contracted from the term micro reciprocal degree, the mired () is a unit of measurement used to express color temperature. Values in mireds are calculated by the formula: M = \frac{1\,000\,000 \,\text{K{T}, where T is the colour temperature in units of kelvins and M denotes the resulting mired dimensionless number. The constant is one million kelvins.

The sthène (; symbol sn), sometimes spelled (or misspelled) sthéne or sthene (from ), is an obsolete unit of force or thrust in the metre–tonne–second system of units (mts) introduced in France in 1919. When proposed by the British Association in 1876, it was called the funal, but the name was changed by 1914. The mts system was abandoned in favour of the mks system and has now been superseded by the International System of Units.

unit for gravitation gradients equal to 10⁻⁹ s⁻²

unit of energy distribution over an area

A rayl (symbol Rayl) is one of two units of specific acoustic impedance and characteristic acoustic impedance; one an MKS unit, and the other a CGS unit. These have the same dimensions as momentum per volume.

The pièze () is the unit of pressure in the metre–tonne–second system of units (mts system), used, e.g., in the former Soviet Union 1933–1955. It is defined as one sthène per square metre. The symbol is pz.

unit of speed

predecessor of the kilogram

The Kilopondmetre is an obsolete unit of torque and energy in the gravitational metric system. It is abbreviated kp·m or m·kp, older publications often use m­kg and kg­m as well.

A thermie (th) is a non-SI metric unit of heat energy, part of the metre-tonne-second system sometimes used by European engineers. The thermie is equal to the amount of energy required to raise the temperature of of water at at standard atmospheric pressure by . The thermie is equivalent to , or .

fictional character

obsolete unit of pressure

outdated unit of illuminance