Convert Decibars to Centimeters of Water

Formula

cmH₂O = dbar × 101.9716212978

Derivation from SI units:

• 1 dbar = 10⁻¹ bar = 10⁴ Pa
• 1 cmH₂O = 1000 kg/m³ × 9.80665 m/s² × 0.01 m = 98.0665 Pa
• 1 dbar = 10000 Pa ÷ 98.0665 Pa per cmH₂O = 101.9716212978 cmH₂O

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

Worked examples

1. A reading of 50 dbar converts to 5098.581065 cmH₂O.
   50 dbar × 101.9716213 = 5098.581065 cmH₂O
2. A value of 1000 dbar is 101971.6213 cmH₂O.
   1000 dbar × 101.9716213 = 101971.6213 cmH₂O

Where it's used

Decibars are used for oceanography: CTD instruments report sea pressure in dbar, while centimeters of water appear in mechanical ventilation (PEEP 5–10 cmH₂O, plateau pressure under 30 cmH₂O). Both measure pressure, stress and differential pressure (force per unit area), so the conversion is a fixed factor.

Decibar 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, "bar", with SI prefix deci (10⁻¹).
• 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.