# Millimeter of water conversions

pressure conversions » millimeter of water conversionsThe millimeter of water conversion selector here selects the pressure/stress measurement unit to convert to starting from millimeters of water (mmH2O). To make a conversion starting from a unit of pressure other than millimeter of water, simply click on the "Reset" button.

## What is millimeter of water?

The **millimetre of water** (or **millimeter of water**) is a unit of pressure equal to 9.80638 pascals (1 mmH2O = 9.80638 Pa), the SI derived unit of pressure. It is also equal to 0.0980638 hectopascals (hPa), or 0.00980638 kilopascals (kPa), or about 0.000096781 atmospheres (atm), or 0.0980638 millibars (mbar), or 0.073554 millimeters of mercury at 0 °C (mmHg), or 0.03937 inches of water at 4 °C (inH2O), or 0.0014223 pounds per square inch (psi), or 0.2048105 pounds per square foot (psf) or 0.073554 torr (Torr).

The millimeters of water is the pressure applied by a column of water one millimeter high at 4 °C in a gravitational field.

The millimeter of water is used to measure lung pressures.

*Notes:*

(i) The SI is an abbreviation for the International System of Units

(ii) The density of water at 4 °C is 0.999972 g/cm3 or approximately 1 g/cm3

(iii) According to the General Conference on Weight and Measures, the standard gravity is 9.80665 m/s² (or 32.1740 ft/s²)

*Symbol:*

mmH2O

*Plural:*

millimeters of water

*Also called:*

millimeter of water (plural: millimeters of water, US spelling)

## Millimeter of water conversions: quick links

A compehensive list with conversions from millimeters of water to other (metric, imperial, or customary) pressure and stress measurement units is shown below.

- millimeter of water to atmosphere (standard) (mmH2O to atm)
- millimeter of water to atmosphere (technical) (mmH2O to at)
- millimeter of water to bar (mmH2O to bar)
- millimeter of water to barye (mmH2O to Ba)
- millimeter of water to centibar (mmH2O to cbar)
- millimeter of water to centimeter of mercury (mmH2O to cmHg)
- millimeter of water to centimeter of water (mmH2O to cmH2O)
- millimeter of water to decibar (mmH2O to dbar)
- millimeter of water to dyne per square centimeter (mmH2O to dyn/cm²)
- millimeter of water to gigabar (mmH2O to Gbar)
- millimeter of water to gigapascal (mmH2O to GPa)
- millimeter of water to hectopascal (mmH2O to hPa)
- millimeter of water to inch of mercury (mmH2O to inHg)
- millimeter of water to inch of water (mmH2O to inH2O)
- millimeter of water to kilobar (mmH2O to kbar)
- millimeter of water to kilogram-force per square centimeter (mmH2O to kgf/cm²)
- millimeter of water to kilogram-force per square millimeter (mmH2O to kgf/mm²)
- millimeter of water to kilopascal (mmH2O to kPa)
- millimeter of water to kip per square inch (mmH2O to ksi)
- millimeter of water to megabar (mmH2O to Mbar)
- millimeter of water to megapascal (mmH2O to MPa)
- millimeter of water to millibar (mmH2O to mbar)
- millimeter of water to millimeter of mercury (mmH2O to mmHg)
- millimeter of water to millipascal (mmH2O to mPa)
- millimeter of water to newton per square meter (mmH2O to N/m²)
- millimeter of water to newton per square millimeter (mmH2O to N/mm²)
- millimeter of water to pascal (mmH2O to Pa)
- millimeter of water to pieze (mmH2O to pz)
- millimeter of water to pound per square foot (mmH2O to psf)
- millimeter of water to pound per square inch (mmH2O to psi)
- millimeter of water to torr (mmH2O to Torr)