Convert Inches of Mercury to Centimeters of Water
Convert Inches of Mercury (inHg) to Centimeters of Water (cmH₂O) instantly and accurately.
Conversion Formula
cmH₂O = inHg × 34.531554
About Inches of Mercury
One inch of mercury (inHg) ≈ 3,386 Pa - the primary barometric pressure unit in US aviation and meteorology. ASOS weather stations, METARs, and altimeter settings in the US report in inHg. Standard sea-level pressure is 29.92 inHg. Altimeters are set to local QNH in inHg to maintain altitude reference. US barometers for home weather stations display inHg. Typical pressure range: 28.5-31.0 inHg in continental weather systems. Record low: ~25.70 inHg (Typhoon Tip, 1979). 1 inHg = 3,386.39 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
| Inches of Mercury (inHg) | Centimeters of Water (cmH₂O) |
|---|---|
| 1 inHg | 34.5316 cmH₂O |
| 2 inHg | 69.0631 cmH₂O |
| 5 inHg | 172.658 cmH₂O |
| 10 inHg | 345.316 cmH₂O |
| 25 inHg | 863.289 cmH₂O |
| 50 inHg | 1726.58 cmH₂O |
| 100 inHg | 3453.16 cmH₂O |