SI Prefixes List

Below, you can find the chart of 24 prefixes introduced and governed by
*Bureau International des Poids et Mesures* (eng. *International Bureau of Weights and Measures* )
.The abbreviation SI is from the French language name Système International d’Unités
(eng: International System of Units )

Prefix | Symbol | 10^{n} |
Long/Short Scale |
---|---|---|---|

yotta (gr. okto - eight) |
Y | 10^{24} |
Quadrillion/Septillion |

zetta (lat. septem - seven) |
Z | 10^{21} |
Trilliard/Sextillion |

exa (gr. ex - six) |
E | 10^{18} |
Trillion/Quintillion |

peta (gr. penta - five) |
P | 10^{15} |
Billiard/Quadrillion |

tera (gr. teras – monster) |
T | 10^{12} |
Billion/Trillion |

giga (gr. gigas – giant) |
G | 10^{9} |
Milliard/Billion |

mega (gr. megas – great) |
M | 10^{6} |
Million/Million |

kilo (gr. khilioi – thousand) |
k | 10³ | Thousand/Thousand |

hecto (gr. hekaton – hundred) |
h | 10² | Hundred/Hundred |

deca (gr. deka – ten) |
da | 10^{1} |
Ten/Ten |

10^{0} |
One/One | ||

decy (lat. decimus – tenth) |
d | 10^{-1} |
Tenth/Tenth |

centy (lac. centum – hundredth) |
c | 10^{-2} |
Hundredth/Hundredth |

milli (lac. mille – thousand) |
m | 10^{-3} |
Thousandth/Thousandth |

mikro (gr. mikros – small) |
µ | 10^{-6} |
Millionth/Millionth |

nano (gr. nanos – dwarf) |
n | 10^{-9} |
Milliardth/Billionth |

pico (it. piccolo – small) |
p | 10^{-12} |
Billionth/Trillionth |

femto (den. femten – fifteen) |
f | 10^{-15} |
Billiardth/Quadrillionth |

atto (den. atten – eighteen) |
a | 10^{-18} |
Trillionth/Quintillionth |

zepto (lat. septem - seven) |
z | 10^{-21} |
Trilliardth/Sextillionth |

yokto (gr. okto - eight) |
y | 10^{-24} |
Quadrillionth/Septillionth |

Short And Long Scale

In most English-speaking countries **short scale** is used. In short scale
Billion prefix (10^{9}) is giga, Trillion prefix (10^{12}) is tera,
Billionth prefix (10^{-9}) is nano, Trillionth prefix (10^{-12} is pico, and so on.

In most European countries**long scale** is used. In long scale
Billion prefix (10^{12}) is tera, Trillion prefix (10^{18}) is exa,
Billionth prefix (10^{-12}) is pico, Trillionth prefix (10^{-18}) is atto, and so on.

In most European countries

Prefixes In Computing

Prefixes K,M,G,T,P (kilo,mega,giga,tera,peta) are commonly used in computing,
where they are applied to information and storage units. Since informational systems are based
on power of 2, this led to following meaning of prefixes in computer science:

See also: Data Capacity Converter

Prefix | Symbol | 2^{n} | Decimal Value |
---|---|---|---|

kilo | K | 2^{10} | 1 024 |

mega | M | 2^{20} | 1 048 576 |

giga | G | 2^{30} | 1 073 741 824 |

tera | T | 2^{40} | 1 099 511 627 776 |

peta | P | 2^{50} | 1 125 899 906 842 624 |