Rules governing use of prefixes:
- Prefixes are generally used to maintain numerical values between 0.1 and 100
- Prefixes are generally used for powers of 3 (e.g. kilo for 10³). Use of hecto, deca, deci and centi should generally be avoided except when dealing with small areas or volumes.
| Prefix | Symbol | Multiplication Factor | 10n |
| exa | E | 1 000 000 000 000 000 000 | 1018 |
| peta | P | 1 000 000 000 000 000 | 1015 |
| tera | T | 1 000 000 000 000 | 1012 |
| giga | G | 1 000 000 000 | 109 |
| mega | M | 1 000 000 | 106 |
| kilo | K | 1 000 | 103 |
| hecto | h | 100 | 102 |
| deca | da | 10 | 101 |
| 1 | 100 | ||
| deci | d | 0.1 | 10-1 |
| centi | c | 0.01 | 10-2 |
| milli | m | 0.001 | 10-3 |
| micro | µ | 0.000 001 | 10-6 |
| nano | n | 0.000 000 001 | 10-9 |
| pico | p | 0.000 000 000 001 | 10-12 |
| femto | f | 0.000 000 000 000 001 | 10-15 |
| atto | a | 0.000 000 000 000 000 001 | 10-18 |