# Convert Speed of light [c] to...

Speed of light | |
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Unit system | other |

Unit of | speed |

Symbol | c |

Unit conversions | |

1 c in ... |
... is equal to ... |

SI units | 2.9979×10^{8} m·s^{-1} |

Imperial/US unit(s) | 6.7062×10^{8} mph |

Other unit(s) | 5.8275×10^{8} knot |

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**using**

Metric | Conversion |
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Kilometre per second [km/s] | |

Metre per second [m/s] | |

Kilometre per hour [km/h] | |

Millimetre per second [mm/s] | |

Micrometre per second [µm/s] |

Imperial/US | Conversion |
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Mile per second | |

Mile per hour [mph] | |

Foot per second [ft/s] |

Nautical | Conversion |
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Knot |

Other | Conversion |
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Speed of light [c] | |

Speed of sound | |

Human walk | |

Common snail |

The **speed of light** in vacuum, commonly denoted c, is a universal physical constant important in many areas of physics. Its exact value is 299792458 metres per second (approximately 3.00×10^{8} m/s approximately 186282 mi/s).

According to special relativity, c is the maximum speed at which all matter and hence information in the universe can travel. It is the speed at which all massless particles and changes of the associated fields (including light, a type of electromagnetic radiation, and gravitational waves) travel in vacuum.

This article uses material from the Wikipedia article "Speed of light", which is released under the Creative Commons Attribution-Share-Alike License 3.0.