As of Version 9, the new units framework can be used via Quantity in place of the Units` package.

The Units` package provided a selection of commonly used units found in various scientific fields. The units framework provided by Quantity replaces these completely.

All the previous units are given as fundamental units in the new system, which are represented as strings inside Quantity expressions. Functions such as Convert, ConvertTemperature, and SI have been integrated into UnitConvert, which can take either a target unit or target unit system.

Conversion Functions

Units`	Version 9
Convert[expr, newunits]	UnitConvert[quantity, newunits]
ConvertTemperature[expr, newunits]	UnitConvert[quantity, newunits]
SI[expr]	UnitConvert[quantity, "SI"]

SI Prefixes

SI prefixes such as kilo, micro, and yotta have been integrated into the applicable SI units to form distinct unit names, such as "kilometers" and "yottaseconds".

Quantity and Units

Quantity uses canonical unit names, most of which are the plural forms of the old unit names, but also includes the ability to interpret unknown unit names automatically.

There are equivalents for all units included in the Units` package, and many more beyond that.

Length Units

Units`	Version 9
Angstrom	Quantity["Angstroms"]
AU	Quantity["AstronomicalUnit"]
AstronomicalUnit	Quantity["AstronomicalUnit"]
Bolt	Quantity["BoltsLength"]
Cable	Quantity["CableLengthsUSNavy"]
Caliber	Quantity["Calibres"]
Centimeter	Quantity["Centimeters"]
Chain	Quantity["GuntersChains"]
Cicero	Quantity["Ciceros"]
Cubit	Quantity["Cubits"]
Didot	Quantity["DidotPoints"]
DidotPoint	Quantity["DidotPoints"]
Diopter	Quantity["Diopters"]
Ell	Quantity["Ells"]
Fathom	Quantity["Fathoms"]
Feet	Quantity["Feet"]
Fermi	Quantity["Fermis"]
Foot	Quantity["Feet"]
Furlong	Quantity["Furlongs"]
Hand	Quantity["HandsUnit"]
Inch	Quantity["Inches"]
Kayser	Quantity["Kaysers"]
League	Quantity["Leagues"]
LightYear	Quantity["LightYears"]
Link	Quantity["GuntersLinks"]
Meter	Quantity["Meters"]
Micron	Quantity["Microns"]
Mil	Quantity["Mils"]
Mile	Quantity["Miles"]
NauticalMile	Quantity["NauticalMiles"]
Parsec	Quantity["Parsecs"]
Perch	Quantity["PerchesLength"]
Pica	Quantity["Picas"]
Pole	Quantity["Poles"]
PrintersPoint	Quantity["DesktopPublishingPoints"]
Rod	Quantity["Rods"]
Rope	Quantity["Ropes"]
Skein	Quantity["Skeins"]
Stadion	Quantity["GreekStadions"]
Stadium	Quantity["StadiaCommon"]
StatuteMile	Quantity["Miles"]
SurveyMile	Quantity["SurveyMiles"]
XUnit	Quantity["XUnits"]
Yard	Quantity["Yards"]

Mass and Weight Units

Units`	Version 9
AMU	Quantity["AtomicMassUnit"]
AssayTon	Quantity["AssayShortTons"]
AtomicMassUnit	Quantity["AtomicMassUnit"]
AvoirdupoisOunce	Quantity["Ounces"]
AvoirdupoisPound	Quantity["Pounds"]
Bale	Quantity["BalesOfCotton"]
Carat	Quantity["Carats"]
Cental	Quantity["Centals"]
Dalton	Quantity["Daltons"]
Drachma	Quantity["AtticDrachmes"]
Geepound	Quantity["GeepoundsMass"]
Grain	Quantity["Grains"]
Gram	Quantity["Grams"]
GrossHundredweight	Quantity["LongHundredweights"]
Hundredweight	Quantity["LongHundredweights"]
Kilogram	Quantity["Kilograms"]
Libra	Quantity["RomanLibras"]
LongTon	Quantity["LongTons"]
MetricTon	Quantity["MetricTons"]
Mina	Quantity["AtticMinas"]
NetHundredweight	Quantity["ShortHundredweights"]
Obolos	Quantity["AtticObols"]
Ounce	Quantity["Ounces"]
Pennyweight	Quantity["Pennyweights"]
Pondus	Quantity["DutchPonds"]
Pound	Quantity["Pounds"]
Quintal	Quantity["Quintals"]
Shekel	Quantity["ShekelsMass"]
ShortHundredweight	Quantity["ShortHundredweights"]
ShortTon	Quantity["ShortTons"]
Slug	Quantity["SlugsMass"]
SolarMass	Quantity["SolarMass"]
Stone	Quantity["Stones"]
Talent	Quantity["GreekTalents"]
Ton	Quantity["ShortTons"]
Tonne	Quantity["MetricTons"]
TroyOunce	Quantity["TroyOunces"]

Temperature Units

Units`	Version 9
Celsius	Quantity["DegreesCelsius"] Quantity["DegreesCelsiusDifference"]
Centigrade	Quantity["DegreesCelsius"] Quantity["DegreesCelsiusDifference"]
Fahrenheit	Quantity["DegreesFahrenheit"] Quantity["DegreesFahrenheitDifference"]
Kelvin	Quantity["Kelvins"] Quantity["KelvinsDifference"]
Rankine	Quantity["DegreesRankine"] Quantity["DegreesRankineDifference"]

Temperature units include both absolute temperatures and temperature differences, which are treated as distinct units. For more information see the tutorial on temperature units.

Volume Units

Units`	Version 9
Bag	Quantity["BagsUS"]
Barrel	Quantity["BarrelsOfOil"]
BoardFoot	Quantity["BoardFeet"]
Bucket	Quantity["BucketsUS"]
Bushel	Quantity["BushelsUS"]
Butt	Quantity["ButtsUS"]
Cord	Quantity["Cords"]
Ephah	Quantity["Ephahs"]
Fifth	Quantity["Fifths"]
Firkin	Quantity["FirkinsUS"]
FluidDram	Quantity["FluidDrams"]
FluidOunce	Quantity["FluidOunces"]
Gallon	Quantity["Gallons"]
Gill	Quantity["Gills"]
Hogshead	Quantity["HogsheadsUS"]
ImperialGallon	Quantity["GallonsUK"]
ImperialPint	Quantity["PintsUK"]
Jeroboam	Quantity["Jeroboams"]
Jigger	Quantity["Jiggers"]
Liter	Quantity["Liters"]
Magnum	Quantity["Magnums"]
Minim	Quantity["MinimsUS"]
Noggin	Quantity["NogginsUS"]
Omer	Quantity["Omers"]
Peck	Quantity["Pecks"]
Pint	Quantity["Pints"]
Pony	Quantity["PoniesUS"]
Puncheon	Quantity["PuncheonsUS"]
Quart	Quantity["Quarts"]
RegisterTon	Quantity["RegisterTon"]
Seam	Quantity["SeamsUS"]
Shot	Quantity["Shots"]
Stere	Quantity["Steres"]
Tablespoon	Quantity["Tablespoons"]
Teaspoon	Quantity["Teaspoons"]
Tun	Quantity["Tuns"]
UKGallon	Quantity["GallonsUK"]
UKPint	Quantity["PintsUK"]
WineBottle	Quantity["WineBottle750Milliliter"]

Area Units

Units`	Version 9
Acre	Quantity["Acres"]
Are	Quantity["Ares"]
Barn	Quantity["Barns"]
Hectare	Quantity["Hectares"]
Rood	Quantity["ScottishRods"]
Section	Quantity["SectionsArea"]
Township	Quantity["Townships"]

Time Units

Units`	Version 9
Century	Quantity["Centuries"]
Day	Quantity["Days"]
Decade	Quantity["Decades"]
Fortnight	Quantity["Fortnights"]
Hour	Quantity["Hours"]
Millennium	Quantity["Millennia"]
Minute	Quantity["Minutes"]
Month	Quantity["Months"]
Second	Quantity["Seconds"]
SiderealSecond	Quantity["SiderealSeconds"]
SiderealYear	Quantity["SiderealYears"]
TropicalYear	Quantity["TropicalYears"]
Week	Quantity["Weeks"]
Year	Quantity["Years"]

Force, Energy, and Power Units

Units`	Version 9
BritishThermalUnit	Quantity["BritishThermalUnitsIT"]
BTU	Quantity["BritishThermalUnitsIT"]
Calorie	Quantity["LargeCalories"]
ChevalVapeur	Quantity["ChevalVapeurs"]
Dyne	Quantity["Dynes"]
ElectronVolt	Quantity["Electronvolts"]
Erg	Quantity["Ergs"]
GramWeight	Quantity["GramsForce"]
Horsepower	Quantity["HorsepowerMechanical"]
Joule	Quantity["Joules"]
KilogramForce	Quantity["KilogramsForce"]
KilogramWeight	Quantity["KilogramWeight"]
Newton	Quantity["Newtons"]
Poundal	Quantity["Poundals"]
PoundForce	Quantity["PoundsForce"]
PoundWeight	Quantity["PoundsForce"]
Rydberg	Quantity["Rydbergs"]
Therm	Quantity["Therms"]
TonForce	Quantity["LongTonsForce"]
Watt	Quantity["Watts"]

Pressure Units

Units`	Version 9
Atmosphere	Quantity["Atmospheres"]
Bar	Quantity["Bars"]
Barye	Quantity["Baryes"]
InchMercury	Quantity["InchesOfMercury"]
MillimeterMercury	Quantity["MillimetersOfMercury"]
Pascal	Quantity["Pascals"]
PoundsPerSquareInch	Quantity["PoundsForce"/"Inches"^2]
PSI	Quantity["PoundsForce"/"Inches"^2]
Torr	Quantity["Torr"]

Electromagnetism Units

Units`	Version 9
Abampere	Quantity["ABAmperes"]
Abcoulomb	Quantity["ABCoulombs"]
Abfarad	Quantity["ABFarads"]
Abhenry	Quantity["ABHenries"]
Abmho	Quantity["ABMhos"]
Abohm	Quantity["ABOhms"]
Abvolt	Quantity["ABVolts"]
Amp	Quantity["Amperes"]
Ampere	Quantity["Amperes"]
Biot	Quantity["Biots"]
BohrMagneton	Quantity["BohrMagneton"]
Coulomb	Quantity["Coulombs"]
Farad	Quantity["Farads"]
Gauss	Quantity["Gausses"]
Gilbert	Quantity["Gilberts"]
Henry	Quantity["Henries"]
Maxwell	Quantity["Maxwells"]
Mho	Quantity["Mhos"]
NuclearMagneton	Quantity["NuclearMagnetons"]
Oersted	Quantity["Oersteds"]
Ohm	Quantity["Ohms"]
Siemens	Quantity["Siemens"]
Statampere	Quantity["StatAmperes"]
Statcoulomb	Quantity["StatCoulombs"]
Statfarad	Quantity["StatFarads"]
Stathenry	Quantity["StatHenries"]
Statohm	Quantity["StatOhms"]
Statvolt	Quantity["StatVolts"]
Tesla	Quantity["Teslas"]
Volt	Quantity["Volts"]
Weber	Quantity["Webers"]

Illumination Units

Units`	Version 9
Apostilb	Quantity["Apostilbs"]
Candela	Quantity["Candelas"]
Candle	Quantity["Candle"]
FootCandle	Quantity["FootCandle"]
Hefner	Quantity["HefnerKerzen"]
Lambert	Quantity["Lamberts"]
Lumerg	Quantity["Lumergs"]
Lumen	Quantity["Lumens"]
Lux	Quantity["Lux"]
Nit	Quantity["Nits"]
Phot	Quantity["Phots"]
Stilb	Quantity["Stilbs"]
Talbot	Quantity["Talbots"]

Information Units

Units`	Version 9
Baud	Quantity["Bits"/"Seconds"]
Bit	Quantity["Bits"]
Nibble	Quantity["Nibbles"]

Radiation Units

Units`	Version 9
Becquerel	Quantity["Becquerels"]
Curie	Quantity["Curies"]
GrayDose	Quantity["Grays"]
Rad	Quantity["Rads"]
Roentgen	Quantity["Roentgens"]
Rontgen	Quantity["Roentgens"]
Rutherford	Quantity["Rutherfords"]

Viscosity Units

Units`	Version 9
Poise	Quantity["Poise"]
Reyn	Quantity["Reyns"]
Rhes	Quantity["Rhes"]
Stokes	Quantity["Stokes"]

Unit Multipliers

Units`	Version 9
ArcMinute	Quantity["ArcMinutes"]
ArcSecond	Quantity["ArcSeconds"]
BakersDozen	Quantity["BakersDozens"]
Dozen	Quantity["Dozens"]
Grade	Quantity["Grads"]
Gross	Quantity["Grosses"]
Percent	Quantity["Percent"]
Quadrant	Quantity[π/2,"Radians"]
RightAngle	Quantity["RightAngles"]

Other Units

Units`	Version 9
Denier	Quantity["Denier"]
Gal	Quantity["Galileos"]
Gravity	Quantity["StandardAccelerationOfGravity"]
Hertz	Quantity["Hertz"]
Knot	Quantity["Knots"]
Mole	Quantity["Moles"]
Radian	Quantity["Radians"]
Steradian	Quantity["Steradians"]

Note especially that the units in the kernel are expressed as strings in plural form.

Unitless forms for dimensionless units can be derived with 1 as the unit.

Some of the values from the previous conversions will be slightly different from the old package. In some cases, this is the result of updated scientific research. (The Hubble constant can be considered an example of this.) In others, a slightly different standard was used for deriving the value, as in the case of the speed of sound in air. Finally, the so-called solar constant (and associated solar luminosity) provides an exception, as it is not in fact constant, and the current value more correctly reflects the solar cycle.