The following are the only units of measurement that are approved by the International System of Units (or SI for short). All other forms of measurement can
be derived by using them in special equations.
Metric Units
Name 
Symbol 
Measures 
Meter 
m 
Length 
Kilogram 
kg 
Mass 
Second 
s 
Time 
Ampere 
A 
Electric Current 
Kelvin 
K 
Thermodynamic Temperature 
Mole 
mol 
Amount of Substance 
Candela 
cd 
Luminous Intensity 

These are the derived units that come from the standard units, and the equation for deriving them.
Derived Units
Measured 
Unit Name 
Equation 
Area 
Square Meter 
m^{2} 
Volume 
Cubic Meter 
m^{3} 
Speed / Velocity 
Meter Per Second 
m/s 
Acceleration 
Meter Per Second Squared 
m/s^{2} 
Wave Number 
Reciprocal Meter 
m^{1} 
Mass Density 
Kilogram Per Cubic Meter 
kg/m^{3} 
Specific Volume 
Cubic Meter Per Kilogram 
m^{3}/kg 
Current Density 
Ampere Per Square Meter 
A/m^{2} 
Magnetic Field Strength 
Ampere Per Meter 
A/m 
Amount of Substance Concentration 
Mole Per Cubic Meter 
mol/m^{3} 
Luminance 
Candela Per Square Meter 
cd/m^{2} 
Mass Fraction 
Kilogram per Kilogram (1) 
kg/kg 

Prefixes are placed in front of units in order to quickly and simply change the scale of measurement. This is the complete prefix table according to SI.
Metric Prefixes
Factor 
Name 
Symbol 
Example 
10 ^{24} 
Yotta 
Y 
1,000,000,000,000,000,000,000,000 
10 ^{21} 
Zetta 
Z 
1,000,000,000,000,000,000,000 
10 ^{18} 
Exa 
E 
1,000,000,000,000,000,000 
10 ^{15} 
Peta 
P 
1,000,000,000,000,000 
10 ^{12} 
Tera 
T 
1,000,000,000,000 
10 ^{9} 
Giga 
G 
1,000,000,000 
10 ^{6} 
Mega 
M 
1,000,000 
10 ^{3} 
Kilo 
k 
1,000 
10 ^{2} 
Hecto 
h 
100 
10 ^{1} 
Deka 
da 
10 
10 ^{0} 
None 
 
1 
10 ^{1} 
Deci 
d 
.1 
10 ^{2} 
Centi 
c 
.01 
10 ^{3} 
Milli 
m 
.001 
10 ^{6} 
Micro 
µ 
.000001 
10 ^{9} 
Nano 
n 
.000000001 
10 ^{12} 
Pico 
p 
.000000000001 
10 ^{15} 
Femto 
f 
.000000000000001 
10 ^{18} 
Atto 
a 
.000000000000000001 
10 ^{21} 
Zepto 
z 
.000000000000000000001 
10 ^{24} 
Yocto 
y 
.000000000000000000000001 

More Informaiton
National Institute of Standards and Technology (Measurements Section)

© Copyright 2003: Dean Tersigni. All rights reserved.
