BACKGROUND INFORMATION
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).
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 | 10^{9} | 1 000 000 000 | billion** |
mega | M | 10^{6} | 1 000 000 | million |
kilo | k | 10^{3} | 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. |
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 | m² | |||
hectare | ha | 1 ha | = | 10 000 m² | |
square kilometer | km² | 1 km² | = | 100 ha | |
Volume | milliliter | mL | 1000 mL | = | 1 L |
cubic centimeter | cm³ | 1 cm³ | = | 1 mL | |
liter | L | 1000 L | = | 1 m³ | |
cubic meter | m³ | ||||
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/m³ | |||
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 | kW·h | 1 kW·h | = | 3.6 MJ | |
Electric current | ampere | A |
Metric Conversion --> A link to a metric converter site