Convert Millimeters of Mercury to Centimeters of Water
Convert Millimeters of Mercury (mmHg) to Centimeters of Water (cmH₂O) instantly and accurately.
Conversion Formula
cmH₂O = mmHg × 1.35951
About Millimeters of Mercury
One millimetre of mercury (mmHg) = pressure from 1 mm of mercury at 0°C and standard gravity = 133.322 Pa. Clinical medicine worldwide uses mmHg for blood pressure (normal ~120/80 mmHg) and for gas partial pressures in physiology: arterial O₂ ~95-100 mmHg; CO₂ ~40 mmHg; alveolar O₂ ~104 mmHg. Ophthalmologists measure intraocular pressure in mmHg (normal 10-21; glaucoma risk above 21). Vacuum equipment ratings are also given in mmHg. 760 mmHg = 1 atm. 1 mmHg = 133.322 Pa.
About Centimeters of Water
One centimetre of water column (cmH₂O) ≈ 98.07 Pa - the clinical pressure unit for respiratory and intravascular measurements. Mechanical ventilator settings are in cmH₂O: peak inspiratory pressure (PIP) 15-30 cmH₂O; PEEP 5-15 cmH₂O; plateau pressure should stay below 30 cmH₂O to avoid lung injury. Lumbar puncture CSF opening pressure is normally 8-20 cmH₂O. CPAP/BiPAP therapy for sleep apnea: 4-20 cmH₂O. Central venous pressure is also reported in cmH₂O. 1 cmH₂O = 98.0665 Pa.
Quick Reference Table
| Millimeters of Mercury (mmHg) | Centimeters of Water (cmH₂O) |
|---|---|
| 1 mmHg | 1.35951 cmH₂O |
| 2 mmHg | 2.71902 cmH₂O |
| 5 mmHg | 6.79755 cmH₂O |
| 10 mmHg | 13.5951 cmH₂O |
| 25 mmHg | 33.9877 cmH₂O |
| 50 mmHg | 67.9755 cmH₂O |
| 100 mmHg | 135.951 cmH₂O |