# Picometre

The **picometre** (international spelling as used by the International Bureau of Weights and Measures; SI symbol: **pm**) or **picometer** (American spelling) is a unit of length in the International System of Units (SI), equal to 1×10^{−12} m, or one trillionth (1/1000000000000) of a metre, which is the SI base unit of length.

Picometre | |
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General information | |

Unit system | SI |

Unit of | length |

Symbol | pm |

Conversions | |

1 pm in ... | ... is equal to ... |

SI base units | 1×10^{−12} m |

Natural units | 6.1877×10^{22} ℓ_{P}1.8897×10 ^{−2} a_{0} |

imperial/US units | 3.9370×10^{−11} in |

*in Wiktionary, the free dictionary.*

**picometre**The picometre is one thousand femtometres, one thousandth of a nanometre (1/1000 nm), one millionth of a micrometre (also known as a micron), one billionth of a millimetre, and one trillionth of a metre.[2] The symbol μμ was once used for it.[3] It is also one hundredth of an ångström, an internationally known (but non-SI) unit of length.