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Units Calculator




The Fourmilab Units Calculator is based upon the GNU Units utility. It supports expressions in the “Convert” and “To” fields in the same syntax as described in the GNU Units manual. If the To field is left blank, the definition of the unit in the Convert field will be shown in terms of fundamental units. Entering “?” in the To field shows all standard units with the same dimensions as the expression in the Convert field. A total of 3460 linear units, 109 nonlinear units, and 109 prefixes are defined. The most common are listed below; clicking them copies the unit to the input field most recently clicked.

You can define your own units or save intermediate results by prefixing the expression in the Convert field with a variable name beginning with a capital letter followed by letters and numbers (for example “Orbit”). Definitions are shown in the light blue box, and may be used in either the Convert or To fields. Definitions are lost when you reload the page, but may be copied from the definitions box and pasted back later, then reloaded with the “Load” button.

Length: angstrom astronomicalunit cable caliber chain earthradius fathom fermi foot furlong hand inch league lightyear link metre micron mile nauticalmile parsec pica plancklength point rod yard

Mass: atomicmassunit carat dalton dram electronmass grain gram kilogram longton neutronmass ounce pennyweight planckmass pound protonmass quintal slug stone ton tonne troyounce

Time: calendaryear century day decade fortnight gregorianyear hms hour julianyear leapyear lunarmonth millennium minute month plancktime saros second shake siderealday siderealyear synodicmonth time watch week year

Energy: barreloil britishthermalunit btu calorie Calorie electronvolt erg hiroshima joule kWh kcal_mol quad tnt

Force: dyne lbf newton poundal slugf

Pressure: atmosphere bar inH2O inHg mmHg pascal psi torr

Area: A4paper Apaper acre barn hectare legalsize section township USacre

Volume: acrefoot barrel bushel cc cord fluidounce gallon hogshead imperialgallon imperialpint imperialquart jeroboam jigger litre magnum melchior melchizedek methuselah metriccup midas minim nebuchadnezzar peck pint primat quart rehoboam salmanazar solomon sovereign stere tablespoon teaspoon uscup winebottle

Temperature: degC degF degK degR kelvin plancktemperature tempC tempF tempK tempR

Angle: arcminute arcsecond circle degree dms pi quadrant radian revolution rightangle sextant

Solid Angle: sphere sphericalrightangle squaredegree squareminute squaresecond steradian

Velocity: c fps knot kph mach mph

Acceleration: force galileo gravity

Viscosity: poise reyn

Charge: coulomb e

Current: ampere gilbert

Capacitance: farad pf

Resistance: kilohm megohm ohm

Inductance: henry mh

Conductance: mho siemens

Electric Potential: volt

Magnetic Field: gauss oersted tesla

Magnetic Flux: maxwell weber

Luminous Intensity: candela candle lumen

Luminance: footcandle footlambert lambert lux metercandle vmag

Constants: alpha boltzmann c epsilon0 gasconstant G hbar k_C mu0 pi stefanboltzmann wiendisplacement Z0

Prefixes: deka hecto kilo mega giga tera peta exa zetta yotta
deci centi milli micro nano pico femto atto zepto yocto

Astronomy: sunmass mercurymass venusmass earthmass moonmass marsmass jupitermass saturnmass uranusmass neptunemass plutomass
sunradius mercuryradius venusradius earthradius moonradius marsradius jupiterradius saturnradius uranusradius neptuneradius plutoradius

Functions: acosh() acos() asinh() asin() atanh() atan() cosh() cos() cuberoot() exp() ln() log() sinh() sin() sqrt() tanh() tan()

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