Centimeter of Water (cmH₂O)

The conventional centimetre of water (cmH₂O) is the pressure of a 1 cm column of water of density 1000 kg/m³ under standard gravity: exactly 98.0665 Pa.

Symbol: cmH₂O (ASCII: cmH2O)

Quantity: pressure, stress and differential pressure (force per unit area)

SI relation: 1 cmH₂O = 98.0665 Pa (exact)

Derivation: 1 cmH₂O = 1000 kg/m³ × 9.80665 m/s² × 0.01 m = 98.0665 Pa

Exact: yes, by definition

Reference conditions. Conventional water column: ρ = 1000 kg/m³ and gₙ = 9.80665 m/s² (≈ water at 4 °C).

Typical uses

Mechanical ventilation (PEEP 5–10 cmH₂O, plateau pressure under 30 cmH₂O)
CPAP therapy (4–20 cmH₂O)
Central venous and cerebrospinal fluid pressure

Convert centimeters of water to other units

1 cmH₂O in other pressure units
Conversion	1 cmH₂O equals	Reverse
centimeter of water to pascal	98.0665 Pa	pascal to centimeter of water
centimeter of water to kilopascal	0.0980665 kPa	kilopascal to centimeter of water
centimeter of water to psi	0.01422334331 psi	psi to centimeter of water
centimeter of water to bar	0.000980665 bar	bar to centimeter of water
centimeter of water to millimeter of mercury	0.7355591353 mmHg	millimeter of mercury to centimeter of water
centimeter of water to inch of water	0.3937007874 inH₂O	inch of water to centimeter of water
centimeter of water to atmosphere	0.0009678411054 atm	atmosphere to centimeter of water
centimeter of water to megapascal	0.0000980665 MPa	megapascal to centimeter of water
centimeter of water to millibar	0.980665 mbar	millibar to centimeter of water
centimeter of water to torr	0.7355592401 Torr	torr to centimeter of water
centimeter of water to millimeter of water	10 mmH₂O	millimeter of water to centimeter of water
centimeter of water to inch of mercury	0.02895902107 inHg	inch of mercury to centimeter of water
centimeter of water to decibar	0.00980665 dbar	decibar to centimeter of water
centimeter of water to inch of water (60 °F)	0.3940945989 inH₂O (60 °F)	inch of water (60 °F) to centimeter of water
centimeter of water to barye	980.665 Ba	barye to centimeter of water

Open the Pressure Converter to convert any value between all units.

Sources

Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "centimeter of water, conventional (cmH2O)".

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.

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APA

Scientific Converters. (2026, October 15). Centimeter of Water (cmH₂O). Retrieved October 18, 2026, from https://scientificconverters.com/units/centimeter-of-water/

IEEE

Scientific Converters, "Centimeter of Water (cmH₂O)," scientificconverters.com. Accessed: Oct. 18, 2026. [Online]. Available: https://scientificconverters.com/units/centimeter-of-water/