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Derived Metric Units

Table of Derived Metric Units with Special Names

By Todd Helmenstine

The metric or SI (Le Système International d'Unités) system of units has many derived units from the seven base units. A derived unit would be a unit that is a combination of base units. Density would be an example where density = mass/volume or kg/m3.

Many derived units have special names for the properties or measurements they represent. This table lists eighteen of these specialized units along with their basic unit factors. Many of them honor famous scientists for their work in the fields which use these units.

Note the units of radian and steradian do not actually represent any physical property to measure but are understood to be an arc length per radius (radian) or arc length x arc length per radius x radius (steradian). These units are generally considered unitless.

Measurement Derived Unit Name of Unit Combination of Base Units
plane angle rad radian m·m-1 = 1
solid angle sr steradian m2m-2 = 1
frequency Hz hertz s-1
force N newton m·kg/s2
pressure Pa pascal N/m2 or kg/ms2
energy J joule N·m or m2kg/s2
power W watt J/s or m2kg/s3
electric charge C coulomb A·s
electromotive force V volt W/A or m2kg/As3
capacitance F farad C/V or A2s3/kg·m2
electric resistance Ω ohm V/A or kg·m2/A2s4
electric conductance S siemens A/V or A2s4/kg·m2
magnetic flux Wb weber V·s or kg·m2/A·s2
magnetic flux density T tesla Wb/m2 or kg/A2s2
inductance H henry Wb/A or kg·m2/A2s2
luminous flux lm lumen cd·sr or cd
illuminance lx lux lm/m2 or cd/m2
catalytic activity kat katal mol/s

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