THE METRIC SYSTEM

BACKGROUND INFORMATION

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The metric system is an internationally agreed set of units for measurement. Since 1960, the metric system is correctly known as the SI system, which is short for Systeme International d'Unites (International System of Units). However, it is still commonly (although somewhat incorrectly) continues to be referred to as the metric system. It has only seven basic measures (known as units), listed in the following table, of which the first four are in common use and the other three are mainly for technical and scientific purposes.

Type of measure

          Standard Unit         

Symbol

length

meter

m

mass (weight)

kilogram

kg

temperature

degree Kelvin

K

time

second

s

electric current

ampere

A

amount of substance

mole

mol

luminous intensity

candela

cd

Quick Metric Converter - Quick and simple metric conversion...click to convert units.

The original SW for the converters was kindly made available by www.metric4us.com, but has been substantially modified. (for example, to include both USA and Imperial measures).

 

TABLES AND INFOR FROM U.S. Metric Association
(www.metric.org)

The most commonly used metric prefixes

This table shows the most commonly used SI prefixes. For a complete list of SI prefixes, including their origins, see SI prefixes and their etymologies.

Prefix Symbol Factor Numerically Name
giga G 109 1 000 000 000 billion**
mega M 106 1 000 000 million
kilo k 103 1 000 thousand
centi c 10-2 0.01 hundredth
milli m 10-3 0.001 thousandth
micro μ 10-6 0.000 001 millionth
nano n 10-9 0.000 000 001 billionth**
** The terms billion, trillion, etc., can be ambiguous. The terms are used here in the American English sense, but British English traditionally defined billion as a million million, rather than a thousand million. However, recent British usage tends to match the American meanings.

 

Commonly used metric system units and symbols

Quantity measured Unit Symbol Relationship
Length, width,
distance, thickness,
girth, etc.
millimeter mm 10 mm = 1 cm
centimeter cm 100 cm = 1 m
meter m      
kilometer km 1 km = 1000 m
Mass
(weight)*
milligram mg 1000 mg = 1 g
gram g      
kilogram kg 1 kg = 1000 g
metric ton t 1 t = 1000 kg
Time second s      
Temperature degree Celsius C      
Area square meter m      
hectare ha 1 ha = 10 000 m
square kilometer km 1 km = 100 ha
Volume milliliter mL 1000 mL = 1 L
cubic centimeter cm 1 cm = 1 mL
liter L 1000 L = 1 m
cubic meter m      
Speed, velocity meter per second m/s      
kilometer per hour km/h 1 km/h = 0.278 m/s
Density kilogram per cubic meter kg/m      
Force newton N      
Pressure, stress kilopascal kPa      
Power watt W      
kilowatt kW 1 kW = 1000 W
Energy kilojoule kJ      
megajoule MJ 1 MJ = 1000 kJ
kilowatt hour kWh 1 kWh = 3.6 MJ
Electric current ampere A      

 

Metric Conversion  --> A link to a metric converter site