Convert Centimeters of Water to Torr

Formula

Torr = cmH₂O × 0.7355592400691

or Torr = cmH₂O ÷ 1.359509806316

Derivation from SI units:

• 1 cmH₂O = 1000 kg/m³ × 9.80665 m/s² × 0.01 m = 98.0665 Pa
• 1 Torr = 101325/760 Pa = 133.3223684 Pa (1/760 of a standard atmosphere)
• 1 cmH₂O = 98.0665 Pa ÷ 133.3223684211 Pa per Torr = 0.7355592400691 Torr

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

Worked examples

1. A reading of 6 cmH₂O converts to 4.41335544 Torr.
   6 cmH₂O × 0.7355592401 = 4.41335544 Torr
2. A value of 30 cmH₂O is 22.0667772 Torr.
   30 cmH₂O × 0.7355592401 = 22.0667772 Torr

Where it's used

Centimeters of Water are used for mechanical ventilation (PEEP 5–10 cmH₂O, plateau pressure under 30 cmH₂O), while torr appear in vacuum technology and vacuum gauges. Both measure pressure, stress and differential pressure (force per unit area), so the conversion is a fixed factor.

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)".
• 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, "torr (Torr)".

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