# Pressure Conversion Guide

Convert pressure units with the pressure unit converting tool, look up a conversion from the tables, identify a pressure unit and its group association with other pressure units or find the relevant pressure conversion factor in Pascals.

Sections: Converter | Tables | Factors | Groups

Pressure Converter

Converts to

N.B. The above pressure unit converter limits the answer value to 9 significant figures and long values will display in exponential form, e.g. 1.5032e+8 = 150320000.

Pressure Conversion Tables

Choose a look up table for converting a particular pressure unit or for a specific pressure conversion application.

Pressure Unit

bar to psi, inHg, mH2O and ftH2O

psi to mbar, hPa, Bar, inHg, mH2O, inH2O and ftH2O

mH2O to ftH2O, bar, psi and inHg

inH2O to mmH2O, mbar, psi and mmHg

Application Specific

Tyre pressure for cars, trucks, cycles, motorbikes or aircraft

Barometric mbar (hPa) to psi, inhg, mmHg and Torr

Altitude in feet or meters to pressure

Pressure Unit Conversion Factors

The following list shows each pressure unit and its equivalent value converted into Pascals (Pa). The Pascal is the SI unit for measuring pressure.

 Bar converts to 100,000 Pascals exactly Pounds per Square Inch or Pounds Force per Square Inch converts to 6894.75729316836... Pascals mbar, mb or mbr Millibar converts to 100 Pascals exactly Newton per Square Metre converts to 1 Pascal exactly Pascal converts to 1 Pascal exactly (SI unit for pressure) Hectopascal converts to 100 Pascals exactly Kilopascal converts to 1,000 Pascals exactly Megapascal converts to 1,000,000 Pascals exactly Kilogram per Square Centimeter or Kilogram Force per Square Centimetre converts to 98,066.5 Pascals exactly Torr converts to 133.322368421053... Pascals Millitorr converts to 0.133322368421053... Pascals Standard Atmosphere converts to 101,325 Pascals exactly Technical Atmosphere converts to 98,066.5 Pascals exactly Dyne per Square Centimeter converts to 0.1 Pascals exactly Ounce per Square Inch or Ounce Force per Square Inch converts to 430.922330823023... Pascals Tons per Square Inch or Tons Force per Square Inch (uk, long) converts to 15,444,256.3366971... Pascals Tons per Square Inch or Tons Force per Square Inch (usa, short) converts to 13,789,514.5863367... Pascals Tons per Square Foot or Tons Force per Square Foot (usa, short) converts to 95,760.5179606717... Pascals psf or pfsf Pounds per Square Foot or Pounds Force per Square Foot converts to 47.8802589803358... Pascals Gram per Square Centimetre or Gram Force per Square Centimeter converts to 98.0665 Pascals exactly

N.B. Numbers which include [...] on the end are rounded.

Manometric Pressure Unit Conversion Factors

The following units are known as manometric pressure units and are derived from the pressure exerted by a column of liquid under the acceleration of earth's gravity. Each manometric pressure unit is shown with its equivalent value converted into Pascals (Pa). The Pascal is the SI unit for measuring pressure.

Since the pressure of the fluid column can vary with changes in liquid density and local gravity it is important to quantify these factors when using these units and these are highlighted at the bottom of this manometric units section.

The use of manometric units is discouraged by national standard organisations because they do not precisely represent the true pressure and there are differing conventions used for the temperature and density of the liquid which can lead to slightly different values.

 mmH2O, mmWG or mmWC @ 4°C Millimetres of Water Gauge or Millimetres of Water Column at 4 Degrees Celsius converts to 9.80665 Pascals cmH2O, cmWG or cmWC @ 4°C Centimetres of Water Gauge or Centimetres of Water Column at 4 Degrees Celsius converts to 98.0665 Pascals mH2O, mWG or mWC @ 4°C Metres of Water Gauge or Metres of Water Column at 4 Degrees Celsius converts to 9,806.65 Pascals inH2O, inWG or inWC @ 4°C Inches of Water Gauge or Inches of Water Column at 4 Degrees Celsius converts to 249.08891 Pascals ftH2O, ftWG or ftWC @ 4°C Feet of Water Gauge or Feet of Water Column at 4 Degrees Celsius converts to 2,989.06692 Pascals mmHg @ 0°C Millimetres of Mercury at 0 Degrees Celsius converts to 133.322387415 Pascals cmHg @ 0°C Centimetres of Mercury at 0 Degrees Celsius converts to 1,333.22387415 Pascals inHg @ 0°C Inches of Mercury at 0 Degrees Celsius converts to 3,386.388640341 Pascals µHg or µmHg @ 0°C Microns of Mercury or Micrometres of Mercury at 0 degrees Celsius converts to 0.133322387415 Pascals

The above manometric pressure units assume the following in their derivation and although they are not physical constants they have been accepted as popular conventions and are used universally:

Standard acceleration due to gravity of 9.80665m/s^2
Density of pure water at 4 deg C is 1000 kg/m^3
Density of mercury at 0 deg C is 13,595.1 kg/m^3

Pressure Units Grouped by Relationship

Many units have a similar application or derivation, the use of each varies depending on country, industry and pressure value

Pressure units derived from 'Pascal' the SI unit for pressure

Pa, hPa, kPa, MPa, N/m²

bar, mbar, mb, mbr

dyn/cm², dyne/cm², dynes/cm², d/cm²

Force related pressure units

kg/cm², kgf/cm², at, g/cm², gf/cm²

psi, pfsi, lb/in², lbf/in², oz/in², ozf/in²

tsi (uk, long), tfsi (uk, long), tsi (usa, short), tfsi (usa, short), tsf (usa, short), tfsf (usa, short), psf, pfsf

Water related pressure units

mm H2O, cm H2O, m H2O

mm WG, cm WG, m WG

mm WC, cm WC, m WC

in H2O, ft H2O

in WG, ft WG

in WC, ft WC

Mercury related pressure units

mm Hg, cm Hg, in Hg

µ Hg, µm Hg, micron Hg

Pressure units derived from 1 standard atmosphere (1 atm = 101325 Pascals)

atm, Torr, mTorr

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Pressure Conversion

Converts to

IP Ratings Explained

I P

First Digit (Solids)
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Second Digit (Liquids)
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Temperature Conversion

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