What are the common units of pressure? List them in order of smallest to largest unit.

1 Pa, 1 psi, 1 torr, 1 mm Hg, 1 in Hg, 1 atm:

Unit |
Average Air pressure at Sea level |

Pascal (Pa) | 101,325 |

kiloPascal (kPa) | 101,325 |

Atmosphere (atm) | 1 (exactly) |

Millimeters of mercury (mmHg) | 760 |

Inches of mercury (inHg) | 29.92 |

Torr (torr) | 760 |

Pounds per square inch (psi) | 14.7 |

**Answer**: The order from the smallest unit to the largest is: Pascal, Torr, inches of mercury, psi, bar, and atmosphere.

## Explanation

There are many units of measurement with it can express pressure, but the first unit is the millimeters of mercury in the column, which is also called Torr by the inventor of the barometer. The other units are atmosphere (atm), pascal (Pa), pounds per square inch (psi), the bar, and inches of mercury (in Hg). The order from the smallest unit to the largest is Pascal, Torr, inches of mercury, psi, bar, and atmosphere.