Measurement Standards

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 m2
Volume Cubic Meter m3
Speed / Velocity Meter Per Second m/s
Acceleration Meter Per Second Squared m/s2
Wave Number Reciprocal Meter m-1
Mass Density Kilogram Per Cubic Meter kg/m3
Specific Volume Cubic Meter Per Kilogram m3/kg
Current Density Ampere Per Square Meter A/m2
Magnetic Field Strength Ampere Per Meter A/m
Amount of Substance Concentration Mole Per Cubic Meter mol/m3
Luminance Candela Per Square Meter cd/m2
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 .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)

Pointless