# Convert watt-second [Ws] to...

Ws | |
---|---|

Unit system | metric |

Unit of | energy |

Symbol | Ws |

Unit conversions | |

1 Ws in ... |
... is equal to ... |

SI units | 1 J |

Imperial/US unit(s) | 0.73758 ft.lbf |

**I want to convert:**
**using**

Metric | Conversion |
---|---|

MWh | |

kWh | |

Wh | |

MJ | |

kJ | |

J | |

Ws | |

erg | |

eV |

British/Imperial | Conversion |
---|---|

Quad | |

Therm | |

BTU | |

Foot-pound |

Other | Conversion |
---|---|

kcal | |

cal | |

Thermie |

A **watt second** (symbol W s or W·s) is a derived unit of energy equivalent to the joule.

The **watt-second** is the energy equivalent to the power of one watt sustained for one second. While the watt-second is equivalent to the joule in both units and meaning, there are some contexts in which the term "watt-second" is used instead of "joule".

Although joule and **watt-second** mean exactly the same thing (they represent the same amount of the same physical quantity, viz. energy), the newton metre is not equivalent to the joule (despite having the same dimensions) as it represents torque rather than energy. (In terms of vectors, torque is a cross product of force and distance, and energy is their dot product.)

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