The metric system is a system of measurement which uses a unit of length to derive units of mass and capacity. The three basic units are the "meter "(length), the "gram" (mass), and the "liter" (capacity), abbreviated as “m”, “g”, and “l”, respectively. These units are related, so that for practical purposes one cubic centimeter of water has a volume of one milliliter and weighs one gram
The metric units of measurement are formed by combining the name or abbreviation of the basic unit with twenty numerical prefixes representing multiples of ten. For example, one “kilogram” is one thousand grams (1,000 or 103 gram) and abbreviated as “1 kg”. One “micrometer” is one-,millionth of a meter (1/1,000,000th , 0.000001, or 10-6 meter) and abbreviated as “1 μm”.
These metric prefixes can be used to apply to other units of measurement, like “volts” (electricity) or “curies” (radiation).
The metric system was adopted in the mid-1790’s. It is based on the length of the “metre”, originally defined as one ten-millionth of the distance from the North Pole to the Equator.
| Metric Prefix | Description | Abbreviation Symbol |
Multiplier | Exponential |
| yotta | septillion | Y | 1 000 000 000 000 000 000 000 000 | 1024 |
| zetta | sextillion | Z | 1 000 000 000 000 000 000 000 | 1021 |
| ext | quintillion | E | 1 000 000 000 000 000 000 | 1018 |
| peta | quadrillion | P | 1 000 000 000 000 000 | 1015 |
| tera | trillion | T | 1 000 000 000 000 | 1012 |
| giga | billion | B | 1 000 000 000 | 109 |
| mega | million | M | 1 000 000 | 106 |
| kilo | thousand | k | 1 000 | 103 |
| hecto | hundred | h | 100 | 106 |
| deca | ten | da | 10 | 101 |
| basic unit | one | none | 1 | 106 |
| deci | tenth | d | 0.1 | 10-1 |
| centi | hundredth | c | 0.01 | 10-2 |
| milli | thousandth | m | 0.001 | 10-3 |
| micro* | millionth | μ | 0.000 001 | 10-6 |
| nano | billionth | n | 0.000 000 001 | 10-9 |
| pico | trillionth | p | 0.000 000 000 001 | 10-12 |
| femto | quadrillionth | f | 0.000 000 000 000 000 001 | 10-15 |
| atto | quintillionth | a | 0.000 000 000 000 000 000 001 | 10-18 |
| zepto | sextillionth | z | 0.000 000 000 000 000 000 000 001 | 10-21 |
| yocto | septillionth | y | 0.000 000 000 000 000 000 000 000 001 | 10-24 |
| *Note: The abbreviation symbol for “micro” is the Greek letter “mu”. To type the “μ” symbol, use a key pad to type the number “230” while holding down the ALT key. This will not work if using the keyboard number keys above the keyboard row that starts with the letter “Q”. | ||||