Pressure Conversion

Created by Krishna Nelaturu
Last updated: Jul 10, 2022

This pressure conversion tool is perfect for anyone who wishes to convert the units of their pressure measurements. You can even use this calculator for barometric pressure conversion. In this article, we shall discuss the different units of pressure. We shall also look at the pressure conversion table to understand how the unit conversion works.

If you first need to calculate pressure, we recommend our pressure calculator.

What is pressure?

Pressure is the amount of force exerted per unit area perpendicular to the force direction. It is a scalar quantity. The SI unit of pressure is Pascals (Pa). One Pascal (1 Pa) is the pressure exerted by a Newton force (1 N) on a one square meter surface (1 m2).

If you need help converting force and area for your pressure calculations, use our force converter and area converter.

Different pressure units

There are different kinds of pressure, like fluid pressure and barometric pressure, depending on the source. We can measure them all using Pascals, but other units are conveniently available.

  • Pound per square inch (psi): Pound per square inch (or pound-force per square inch) is an avoirdupois unit of pressure caused by one pound-force acting on one square inch area. One pound per square inch (1 psi) approximately equals 6895 Pascals.

  • Bar: Another common unit not part of the SI unit system, the bar is equal to 100,000 Pa (or 100 kPa). It is slightly less than the standard atmospheric pressure at sea level (approximately 1.013 bar). In meteorology, millibars (=10-3 bars) are common worldwide.

  • Hectopascals (hPa): Due to the advent of the SI unit system, many meteorologists use hectopascals for measuring air pressure instead of bar or millibar. It is equal to 100 Pascals (100 Pa). You can use both hPa and bar in this calculator for barometric pressure conversion.

  • Standard atmospheric pressure (atm): The average atmospheric pressure at sea level is approximately equal to 101325 Pascals, which we define as the standard atmospheric pressure (atm).

  • Units based on liquid column manometers: Liquid column manometers are common pressure measurement equipment. They work on the principle of hydrostatic pressure. We can use the depth of the liquid in the manometer as reliable pressure readings:

    • Millimeter of mercury (mmHg): One millimeter of mercury is approximately equal to the standard atmospheric pressure divided by 760, which gives ≈ 133.322368 Pascals.

    • Inches of mercury (inHg): At 60°F, one inch of mercury equals 3376.85 Pascals.

    • Centimeter or millimeter of water (cmH2O or mmH2O): One centimeter of water corresponds to 98.0665 Pascals of pressure. One millimeter of water equals 9.80665 Pascals.

  • Torr: Torr is precisely equal to the standard atmospheric pressure divided by 760. It is approximately 1 mm Hg, and the difference between the two is negligible in most practice.

Pressure conversion table

The following pressure conversion table will aid you in better deciding which unit will serve you best:

Conversion rate between different pressure units.



in Pascals

in psi





Pound per square inch












Standard atmospheric pressure




Millimeters of mercury




Inches of mercury




You can use the conversion rate in this table to derive the proper pressure conversion formula for your desired units. Or you can skip the trouble and simply use our pressure unit converter.

How to use this pressure converter

This pressure converter will help you skip cumbersome unit conversion calculations. You can even use this calculator for air pressure conversion.

  • Enter the pressure value in the field with the appropriate unit symbol. If you don't find the correct unit right away, click on any unit symbol to open a list of other units to choose from.
  • This pressure unit converter will automatically perform the necessary conversion into all the remaining units.
Krishna Nelaturu
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