Inch of mercury Unit | All you need to know

The inch of mercury (inHg) is a widely recognized unit of pressure, often used in meteorology, aviation, and various scientific and industrial applications. It's particularly valuable in measuring barometric pressure and understanding weather patterns.

Definition and Usage

The inch of mercury is defined as the pressure exerted by a column of mercury one inch in height at the standard acceleration due to gravity. This unit is commonly used to describe atmospheric pressure and vacuum levels.

Applications in Meteorology and Aviation

The inch of mercury is integral to several fields:

  • Meteorology: It's used to measure atmospheric pressure and predict weather changes.
  • Aviation: Pilots rely on it to assess altitude and calculate aircraft performance.
  • Vacuum Systems: Engineers apply it to measure pressure in vacuum systems.

Conversions and Equivalents

Understanding conversions of inch of mercury to other pressure units is essential:

  • 1 Inch of Mercury (inHg) = 3.38638867 kPa (kilonewton per square meter)
  • 1 Inch of Mercury (inHg) ≈ 33.8638867 mbar
  • 1 Inch of Mercury (inHg) ≈ 0.0334211 bar
  • 1 Inch of Mercury (inHg) ≈ 0.491154 psi

Usage in Meteorology and Aviation

The inch of mercury plays a vital role in various contexts:

  • Weather Forecasting: It's essential in predicting weather patterns and changes.
  • Altitude Measurement: Pilots use it to calculate aircraft altitude and performance.
  • Barometric Pressure: Inch of mercury helps describe atmospheric pressure.


The inch of mercury (inHg) is a fundamental unit of pressure, especially in meteorology, aviation, and scientific applications. Its significance in measuring atmospheric pressure, altitude, and vacuum levels makes it an indispensable tool for meteorologists, pilots, researchers, and engineers.

Keywords: Inch of Mercury, inHg, pressure unit, meteorology, aviation, conversions