**Full name:** millimeter of water [4 °C]

**Plural form:** millimeters of water

**Symbol:** mmH2O

**Alternate spelling:** mm of water

**Category type:** pressure

**Scale factor:** 9.80665

The SI derived unit for pressure is the pascal.

1 pascal is equal to 0.101971621298 mmH2O.

Valid units must be of the **pressure** type.

You can use this form to select from known units:

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mmH2O to newton/square metre

mmH2O to micrometer of water [4 °C]

mmH2O to petabar

mmH2O to decipascal

mmH2O to inch of air [15 °C]

mmH2O to attobar

mmH2O to pound/square inch [absolute]

mmH2O to exabar

mmH2O to millimeter of water [4 °C]