SI - Metric Prefixes
Some of the physical properties measured by modern science are incredibly large, while others are infinitesimally small. While other measurement systems frequently use different units depending upon scale, the metric system uses the same basic units regardless of size.
Instead of changing units, the metric system leverages a system of prefixes to multiply or divide the standard units. Each prefix can be viewed as a type of shorthand or abbreviation that represents a specific power of ten. For physical properties that are significantly larger than a standard unit, the metric system employs the following set of prefixes:
Units Multiplied: | |||
---|---|---|---|
Prefix | Abbrev. | Decimal Form | Exponent |
deka | da | 10. | 10^{1} |
hecto | h | 100. | 10^{2} |
kilo | k | 1000. | 10^{3} |
Mega | M | 1,000,000. | 10^{6} |
Giga | G | 1,000,000,000. | 10^{9} |
Tera | T | 1,000,000,000,000. | 10^{12} |
Peta | P | 1,000,000,000,000,000. | 10^{15} |
Exa | E | 1,000,000,000,000,000,000. | 10^{18} |
Each prefix can be applied to any of the standard units. Rather than representing a unique unit unto itself, a kilogram is just another way to represent a measurement of 1,000 grams. Physical properties that are significantly smaller than a standard unit, have their own set of prefixes:
Units Divided: | |||
---|---|---|---|
Prefix | Abbrev. | Decimal Form | Exponent |
deci | d | .1 | 10^{-1} |
centi | c | .01 | 10^{-2} |
milli | m | .001 | 10^{-3} |
micro | µ | .0000001 | 10^{-6} |
nano | n | .000000001 | 10^{-9} |
pico | p | .000000000001 | 10^{-12} |
femto | f | .000000000000001 | 10^{-15} |
atto | a | .000000000000000001 | 10^{-18} |
Similar to the way a kilogram represents one thousand (1,000) grams, a milligram is just shorthand for one-thousandth (.001) of a gram. Taken together, these two sets of prefixes form a complete system allowing one to easily describe all aspects of the physical world - from the very large to the very small.
Unit Scale: | ||||
---|---|---|---|---|
Prefix | Abbrev. | Decimal Form | Exponent | |
Exa | E | 1,000,000,000,000,000,000. | 10^{18} | |
Peta | P | 1,000,000,000,000,000. | 10^{15} | |
Tera | T | 1,000,000,000,000. | 10^{12} | |
Giga | G | 1,000,000,000. | 10^{9} | |
Mega | M | 1,000,000. | 10^{6} | |
kilo | k | 1000. | 10^{3} | |
hecto | h | 100. | 10^{2} | |
deka | da | 10. | 10^{1} | |
1. | 10^{0} | |||
deci | d | .1 | 10^{-1} | |
centi | c | .01 | 10^{-2} | |
milli | m | .001 | 10^{-3} | |
micro | µ | .0000001 | 10^{-6} | |
nano | n | .000000001 | 10^{-9} | |
pico | p | .000000000001 | 10^{-12} | |
femto | f | .000000000000001 | 10^{-15} | |
atto | a | .000000000000000001 | 10^{-18} |
Notes:1) The prefixes are technically case-sensitive and there is a huge difference between a Mg. (Megagram) and mg. (milligram).
2) After kilo, the exponents increase by multiples of three, just as the exponents decrease by multiples of three after milli.