It is often the case that numbers are represented with prefixes rather than explicitly indicating powers of \(10\) by using scientific notation. In some cases it may even be the case that prefixes and scientific notation (powers of \(10\)) are used together. For example, the distance to the Moon is approximately \(\text{384,000}\) kilometers or \(3.84 \times 10^5\) km. Since \(1\ \text{km} = 1000\ \text{m}\), the distance to the moon can also be written in meters as \(3.84 \times 10^8\) m. Using prefixes is just a matter of convenience, although prefixes are also a quick way of describing the sizes of quantities.
The table below lists all official prefixes and their powers of \(10\) equivalents. Note that all of the prefixes except one (c for \(10^{-2}\)) are multiples of \(3\). Although there are a other prefixes that are sometimes used, their use is rare and so will not be included here.
| Prefix | Power of 10 | Name | Example |
|---|---|---|---|
| Q | \(10^{30}\) | quetta | \(1\) Qbyte (1 quettabyte) |
| R | \(10^{27}\) | ronna | \(1\) Rbyte (1 ronnabyte) |
| Y | \(10^{24}\) | yotta | \(1\) Ybyte (1 yottabyte) |
| Z | \(10^{21}\) | zetta | \(1\) Zbyte (1 zettabyte) |
| E | \(10^{18}\) | exa | \(1\) Ebyte (1 exabyte) |
| P | \(10^{15}\) | peta | \(1.5\) Pflops (\(1.5\) petaflops |
| T | \(10^{12}\) | tera | \(3\) TB (\(3\) terabytes) |
| G | \(10^9\) | giga | \(10\) Gyr (\(10\) gigayears or \(10\) billion years) |
| M | \(10^6\) | mega | \(80\) MW (\(80\) megawatts) |
| k | \(10^3\) | kilo | \(600\) km (\(600\) kilometers) |
| c | \(10^{-2}\) | centi | \(53\) cm (\(53\) centimeters) |
| m | \(10^{-3}\) | milli | \(0.8\) mg (\(0.8\) milligrams) |
| \(\mu\) | \(10^{-6}\) | micro | \(8\ \mu\)C (\(8.2\) microcoulombs) |
| n | \(10^{-9}\) | nano | \(400\) nm (\(400\) nanometers) |
| p | \(10^{-12}\) | pico | \(0.3\) ps (\(0.3\) picoseconds) |
| f | \(10^{-15}\) | femto | \(1.5\) fm (\(1.5\) femtometers) |
| a | \(10^{-18}\) | atto | \(24.2\) attoseconds |
| z | \(10^{-21}\) | zepto | \(247\) zeptoseconds |
| y | \(10^{-24}\) | yocto | \(0.247\) yoctoseconds |
| r | \(10^{-27}\) | ronto | \(1.67\) rontograms |
| q | \(10^{-30}\) | quecto | \(0.91\) quectograms |