Derived units with special names and symbols

For convenience, certain coherent derived units have been given special names and symbols. There are 22 such units (see Table below). These special names and symbols may themselves be used in combination with the names and symbols for base units and for other derived units to express the units of other derived quantities.

Derived quantity SI coherent derived unit
Name Symbol Expressed
in terms of
other SI units
in terms of
SI base units
plane angle radian rad 1 m/m
solid angle steradian sr 1 m2/m2
frequency hertz Hz s–1
force newton N m kg s–2
pressure, stress pascal Pa N/m2 m–1 kg s–2
energy, work, amount of heat joule J N m m2 kg s–2
power, radiant flux watt W J/s m2 kg s–3
electric charge, amount of electricity coulomb C s A
electric potential difference,
electromotive force
volt V W/A m2 kg s–3 A–1
capacitance farad F C/V m–2 kg–1 s4 A2
electric resistance ohm Ω V/A m2 kg s–3 A–2
electric conductance siemens S A/V m–2 kg–1 s3 A2
magnetic flux weber Wb V s m2 kg s–2 A–1
magnetic flux density tesla T Wb/m2 kg s–2 A–1
inductance henry H Wb/A m2 kg s–2 A–2
Celsius temperature degree Celsius °C K
luminous flux lumen lm cd sr cd
illuminance lux lx lm/m2 m–2 cd
activity referred to a radionucleide becquerel Bq s–1
absorbed dose gray Gy J/kg m2 s–2
dose equivalent,
ιambient dose equivalent,
directional dose equivalent,
personal dose equivalent
sievert Sv J/kg m2 s–2
catalytic activity katal kat s–1 mol