S.I. Units

Basic Units
Physical quantity	SI Unit	Other Units
length	metre, m	km, cm, mm Angstrom, Å = 10-10 m
mass	kilogram, kg	g, mg
time	second, s	ms
temperature	kelvin, K	degrees Celsius, °C
current	ampere, A	mA, μA
amount	mole, mol
Derived Units
Physical quantity	SI Unit	Other Units
area	square metre, m2	cm2 , mm2
volume	cubic metre, m3	cm3 = ml, dm3 = litre (l)
concentration	mol/dm3, mol/l	g/l, g/cm3
density	kilogram per cubic metre, kg/m3	g/cm3
force	newton, N
moment	newton metre, N·m
pressure	pascal, Pa or N/m2	N/cm2
speed/velocity	metre per second, m/s	km/h
acceleration	metre per second squared, m/s2	or (m/s)/s
energy	joule, J	kJ
electrical energy	kilowatt-hour, kWh
power	watt, W	kilowatt, kW
frequency	hertz, Hz (or /s)	kilohertz, kHz
electrical charge	coulomb, C
potential difference	volt, V
resistance	ohm, Ω	kilohm, kΩ
gravitational field strength	N/kg
sound intensity	decibel, dB
Other Time Units
time	day, d	1 d = 24 h
time	hour, h	1 h = 60 min
time	minute, min	1 min = 60 s

Notes

'SI' is short for International System of Units, from the French title Système International d'Unités.

Make sure you use the correct case for unit symbols. E.g. A length in metres is always given with a lower case 'm', never an upper case 'M'.

External Links

Physics Laboratory of NIST

www.physics.nist.gov/cuu/index.html
Constants, Units (SI) and Uncertainty - This is an excellent reference about SI Units and prefixes including their historical context.

©8886 01-Dec-2003