Weill Cornell Medicine Care Discover Teach

Unit Conversion: Pressure

All calculations should be independently verified prior to clinical use. These calculators are intended to supplement, not replace, clinical judgment.

Convert between mmHg, cmH2O, kPa, and PSI. Enter a value in any row and click Calculate to populate the other three.

Unit Value
mmHg
cmH2O
kPa
PSI

All conversions are relative to mmHg as the anchor unit, using the following exact factors from the original calculator:

1 mmHg = 1.36 cmH2O = 0.133 kPa = 0.01934 PSI

A Pascal (Pa) is defined as one newton per square metre (N/m²). A kilopascal (kPa) = 1,000 Pa. Rounding errors may accumulate with multiple sequential conversions between units.

Common clinical pressure reference values:

Measurement mmHg cmH2O kPa
Normal MAP (adult) 70–100 95–136 9.3–13.3
Normal CVP 2–8 3–11 0.3–1.1
Normal ICP 5–15 7–20 0.7–2.0
Typical ventilator PEEP 4–8 5–11 0.5–1.1
Typical peak airway pressure 15–30 20–41 2.0–4.0
Atmospheric pressure (sea level) 760 1,034 101.3

References

  1. Bureau International des Poids et Mesures (BIPM). The International System of Units (SI). 9th ed. BIPM; 2019. Available at: bipm.org.