Femto
Femto is a prefix (see all prefixes) to a unit and means that it is 10-15 times this unit, or, one quindecillionth (European) or one quadrillionth (American). Examples are one femtosecond or one femtometre.
Adopted in 1964, it comes from the Danish or Norwegian femten, meaning fifteen.
| 10n | Prefix | Symbol | Short scale | Long scale | Decimal Equivalent |
|---|---|---|---|---|---|
| 1024 | yotta | Y | Septillion | Quadrillion | 1 000 000 000 000 000 000 000 000 |
| 1021 | zetta | Z | Sextillion | Trilliard (thousand trillion) | 1 000 000 000 000 000 000 000 |
| 1018 | exa | E | Quintillion | Trillion | 1 000 000 000 000 000 000 |
| 1015 | peta | P | Quadrillion | Billiard (thousand billion) | 1 000 000 000 000 000 |
| 1012 | tera | T | Trillion | Billion | 1 000 000 000 000 |
| 109 | giga | G | Billion | Milliard (thousand million) | 1 000 000 000 |
| 106 | mega | M | Million | 1 000 000 | |
| 103 | kilo | k | Thousand | 1 000 | |
| 102 | hecto | h | Hundred | 100 | |
| 101 | deca, deka | da | Ten | 10 | |
| 100 | none | none | One | 1 | |
| 10−1 | deci | d | Tenth | 0.1 | |
| 10−2 | centi | c | Hundredth | 0.01 | |
| 10−3 | milli | m | Thousandth | 0.001 | |
| 10−6 | micro | ยต | Millionth | 0.000 001 | |
| 10−9 | nano | n | Billionth | Milliardth | 0.000 000 001 |
| 10−12 | pico | p | Trillionth | Billionth | 0.000 000 000 001 |
| 10−15 | femto | f | Quadrillionth | Billiardth | 0.000 000 000 000 001 |
| 10−18 | atto | a | Quintillionth | Trillionth | 0.000 000 000 000 000 001 |
| 10−21 | zepto | z | Sextillionth | Trilliardth | 0.000 000 000 000 000 000 001 |
| 10−24 | yocto | y | Septillionth | Quadrillionth | 0.000 000 000 000 000 000 000 001 |
Categories: SI prefixes