System of units

SI Derived Units

Derived quantity Name Symbol Other symbol Base units
plane angle radian rad - m·m-1 = 1
solid angle steradian sr - m2·m-2=1
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, quantity of heat joule J Nm m2·kg·s-2
power, radiant flux watt W J/s m2·kg·s-3
electric charge, quantity 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 conductance siemens S  A/V m-2·kg-1·s3·A2
electric resistance ohm W V/A m2·kg·s-3·A-2
magnetic flux weber Wb Vs 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 m2·m-2·cd = cd
illuminance lux lx lm/m2 m2·m-4·cd = m-2·cd
activity (of a radionuclide) becquerel Bq - s-1
absorbed dose, specific energy (imparted), kerma gray Gy J/kg m2·s-2
dose equivalent sievert Sv J/kg m2·s-2
catalytic activity katal kat - s-1mol
 

SI Unit Prefixes

Prefix Symbol Factor Decimal
Yocto Septillionth y 10-24   0.000000000000000000000001
Zepto Sextillionth z 10-21   0.000000000000000000001
Atto Quintillionth a 10-18   0.000000000000000001
Femto Quadrillionth f  10-15   0.000000000000001
Pico Trillionth p  10-12   0.000000000001
Nano Billionth n  10-9   0.000000001
Micro  Millionth µ  10-6   0.000001
Milli Thousandth m  10-3   0.001
Centi Hundredth c 10-2   0.01
Deci  Tenth d  10-1   0.1
  One   100 1
Deca  Ten da  101 10  
Hecto Hundred h  102 100  
Kilo Thousand k  103 1000  
Mega Million M  106 1000000  
Giga Billion G  109 1000000000  
Tera Trillion T  1012 1000000000000  
Peta Quadrillion P  1015 1000000000000000  
Exa Quintillion E  1018 1000000000000000000  
Zetta Sextillion Z  1021 1000000000000000000000  
Yotta Septillion Y  1024 1000000000000000000000000   
 

SI Base Units

The International System of Units (SI) define the following base units
 

Meter (m)
The length of the path traveled by light in a vacuum during a time interval of 1/299 792 458 of a second.
 

The US Customary System of Measures

The following are the English System of measurement
 

Length
12 inches = 1 foot
3 feet = 1 yard
220 yards = 1 furlong
8 furlongs = 1 mile
5 280 feet = 1 mile
1 760 yards = 1 mile
 

Area
144 square inches = 1 square foot
9 square feet = 1 square yard
4 840 square yards = 1 acre
640 acres = 1 square mile
1 square mile = 1 section
36 sections = 1 township
 

Subscribe to RSS - System of units