Kilo, mega, giga, tera, and peta are among the list of prefixes that are used to denote the quantity of something, such as, in computing and telecommunications, a byte or a bit. Sometimes called prefix multipliers, these prefixes are also used in electronics and physics. Each multiplier consists of a one-letter abbreviation and the prefix that it stands for.
In communications, electronics, and physics, multipliers are defined in powers of 10 from 10-24 to 1024, proceeding in increments of three orders of magnitude (103 or 1,000). In IT and data storage, multipliers are defined in powers of 2 from 210 to 280, proceeding in increments of ten orders of magnitude (210 or 1,024). These multipliers are denoted in the following table.
| Prefix | Symbol(s) | Power of 10 | Power of 2 |
| yocto- | y | 10-24 * | -- |
| zepto- | z | 10-21 * | -- |
| atto- | a | 10-18 * | -- |
| femto- | f | 10-15 * | -- |
| pico- | p | 10-12 * | -- |
| nano- | n | 10-9 * | -- |
| micro- | m | 10-6 * | -- |
| milli- | m | 10-3 * | -- |
| centi- | c | 10-2 * | -- |
| deci- | d | 10-1 * | -- |
| (none) | -- | 100 | 20 |
| deka- | D | 101 * | -- |
| hecto- | h | 102 * | -- |
| kilo- | k or K ** | 103 | 210 |
| mega- | M | 106 | 220 |
| giga- | G | 109 | 230 |
| tera- | T | 1012 | 240 |
| peta- | P | 1015 | 250 |
| exa- | E | 1018 * | 260 |
| zetta- | Z | 1021 * | 270 |
| yotta- | Y | 1024 * | 280 |
| * Not generally used to express data speed | |||
| ** k = 103 and K = 210 | |||