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### Vacuum Pressure Units Conversion Calculator

**Fluids Systems Design and Engineering **

**Vacuum Pressure Units Conversion From Torr to Various Units Calculator **

On the dials of most pressure gauges, atmospheric pressure is assigned the value of zero. Vacuum measurements must have a value of less than zero. Negative gauge pressure is the difference between the system vacuum pressure and atmospheric pressure. Absolute pressure is the pressure (in psia) above a perfect vacuum and is equal to atmospheric pressure less negative gauge pressure.

Other vacuum units are atmospheres, torr, and micrometers. To calculate atmospheres, divide absolute pressure in psia by 14.7. A torr is 1/760 of an atmosphere, and a micrometer is 0.001 torr.

where:

Pressure Torr |
Equivalent |

0.0010 torr | = 1 micrometer of mercury (µm Hg) |

0.0075 torr | = 1 pascal (Pa) |

0.7501 torr | = 1 millibar (mbar) |

1.000 torr | = 1 mm mercury (mm Hg) |

1.868 torr | = 1 in. water at 4°C (in. H_{2}O) |

25.40 torr | = 1 in. mercury (in. Hg) |

51.71 torr | = 1 lb/in^{2} (psi) |

735.6 torr | = 1 tech. atmosphere (at) |

750.1 torr | = 1 bar |

760.0 torr | = 1 standard atmosphere (atm) |

Reference: ASPE