Convert Centimeters of Water to Kilopascals (cmH2O to kPa)

Formula

kPa = cmH₂O × 0.0980665

or kPa = cmH₂O ÷ 10.19716212978

Derivation from SI units:

• 1 cmH₂O = 1000 kg/m³ × 9.80665 m/s² × 0.01 m = 98.0665 Pa
• 1 kPa = 10³ Pa
• 1 cmH₂O = 98.0665 Pa ÷ 1000 Pa per kPa = 0.0980665 kPa

Both units are defined exactly, so the factor is exact. Centimeter of Water definition: centimeter of water; Kilopascal definition: kilopascal.

Worked examples

1. A plateau-pressure limit of 30 cmH₂O is 2.941995 kPa.
   30 cmH₂O × 0.0980665 = 2.941995 kPa
2. 10 cmH₂O is 0.980665 kPa.
   10 cmH₂O × 0.0980665 = 0.980665 kPa

Where it's used

Ventilator settings in cmH₂O are converted to kPa for device standards and scientific papers. One cmH₂O is about 0.098 kPa.

Centimeter of Water to other pressure units

Frequently asked questions

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)".
• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 7, SI prefixes.

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