# Decimal System Prefixes

## Prefix names used for multiples and submultiples units.

Decimal multiples of units:

Prefix | Measure | Decimal equivalent | Exponential expression |
---|---|---|---|

y - yocto | 0.000 000 000 000 000 000 000 001 | E^{-24} | |

z - zepto | 0.000 000 000 000 000 000 001 | E^{-21} | |

a - atto | one-quintillionth | 0.000 000 000 000 000 001 | E^{-18} |

f - femto | one-quadrillionth | 0.000 000 000 000 001 | E^{-15} |

p - pico | one-trillionth | 0.000 000 000 001 | E^{-12} |

n - nano | one-billionth | 0.000 000 001 | E^{-9} |

μ - micro | one-millionth | 0.000 001 | E^{-6} |

m - milli | one-thousandth | 0.001 | E^{-3} |

c - centi | one-hundredth | 0.01 | E^{-2} |

d - deci | one-tenth | 0.1 | E^{-1} |

Uni | one | 1 | E^{0} |

d - deka | ten | 10 | E^{1} |

h - hecto | one hundred | 100 | E^{2} |

k - kilo | one thousand | 1 000 | E^{3} |

M - mega | one million | 1 000 000 | E^{6} |

G - giga | one billion | 1 000 000 000 | E^{9} |

T - tera | one trillion | 1 000 000 000 000 | E^{12} |

P - peta | 1 000 000 000 000 000 | E^{15} | |

E - exa | 1 000 000 000 000 000 000 | E^{18} | |

Z - zetta | 1 000 000 000 000 000 000 000 | E^{21} | |

Y - yotta | 1 000 000 000 000 000 000 000 000 | E^{24} |

Prefixes used in the SI system.