Convert Bar to Centimeters of Water

Formula

cmH₂O = bar × 1019.716212978

Derivation from SI units:

• 1 bar = 10⁵ Pa (exact, by definition)
• 1 cmH₂O = 1000 kg/m³ × 9.80665 m/s² × 0.01 m = 98.0665 Pa
• 1 bar = 100000 Pa ÷ 98.0665 Pa per cmH₂O = 1019.716212978 cmH₂O

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

Worked examples

1. A reading of 2 bar converts to 2039.432426 cmH₂O.
   2 bar × 1019.716213 = 2039.432426 cmH₂O
2. A value of 10 bar is 10197.16213 cmH₂O.
   10 bar × 1019.716213 = 10197.16213 cmH₂O

Where it's used

Bar are used for compressed air and pneumatics (6–8 bar), 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.

Bar 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".
• 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.