This is a list of the Système International d’Unités (SI) prefixes, most commonly used as prefixes in the metric measurement system. Note that the prefixes myria-, hecto-, deka-, deci-, and centi- are avoided in scientific work.
| Prefix | Symbol | Power | Equivalent |
|---|---|---|---|
| Yotta- | Y | 1024 | Septillion |
| Zetta- | Z | 1021 | Sextillion |
| Exa- | E | 1018 | Quintillion |
| Peta- | P | 1015 | Quadrillion |
| Tera- | T | 1012 | Trillion |
| Giga- | G | 109 | Billion |
| Mega- | M | 106 | Million |
| Myria- | my | 104 | Ten thousand |
| Kilo- | k | 103 | Thousand |
| Hecto- | h | 102 | Hundred |
| Deka- | da | 101 | Ten |
| Deci- | d | 10−1 | Tenth |
| Centi- | c | 10−2 | Hundredth |
| Milli- | m | 10−3 | Thousandth |
| Micro- | µ | 10−6 | Millionth |
| Nano- | n | 10−9 | Billionth |
| Pico- | p | 10−12 | Trillionth |
| Femto- | f | 10−15 | Quadrillionth |
| Atto- | a | 10−18 | Quintillionth |
| Zepto- | z | 10−21 | Sextillionth |
| Yocto- | y | 10−24 | Septillionth |