# Millimeter of water conversions

pressure conversions » millimeter of water conversionsThe online converter calculator on this page allows you to select the pressure/stress measurement unit you want 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?

### Definition:

The millimetre 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 known as:

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

Below you can find a comprehensive list with conversions from millimeters of water to other (metric, imperial, or customary) pressure and stress measurement units.