Convert Centimeters of Mercury to Feet of Water
Convert Centimeters of Mercury (cmHg) to Feet of Water (ftH₂O) instantly and accurately.
Conversion Formula
ftH₂O = cmHg × 0.4460334646
About Centimeters of Mercury
One centimetre of mercury (cmHg) = 10 mmHg ≈ 1,333.22 Pa. Historical medical and physiological literature used cmHg for intracardiac and intravascular pressures before mmHg became universal. Left ventricular systolic pressure ~12 cmHg; pulmonary artery systolic 2-3 cmHg. Some older European cardiological textbooks and pre-1970s surgical literature report pressures in cmHg. Central venous pressure, cerebral perfusion pressure, and intra-abdominal pressure are occasionally cited in cmHg in legacy datasets. 1 cmHg = 1,333.22 Pa.
About Feet of Water
One foot of water column (ftH₂O) ≈ 2,989 Pa - the US customary equivalent of cmH₂O used in civil and hydraulic engineering. Municipal water supply systems are designed for 40-80 psi head ≈ 92-184 ft; fire suppression sprinkler systems require minimum 7 psi ≈ 16 ft. Well pump specifications, sump pump head ratings, irrigation mainline pressure, and drainage calculations all use feet of head. 1 ft of water = 12 in WC = 0.4335 psi ≈ 2,989 Pa.
Quick Reference Table
| Centimeters of Mercury (cmHg) | Feet of Water (ftH₂O) |
|---|---|
| 1 cmHg | 0.446033 ftH₂O |
| 2 cmHg | 0.892067 ftH₂O |
| 5 cmHg | 2.23017 ftH₂O |
| 10 cmHg | 4.46033 ftH₂O |
| 25 cmHg | 11.1508 ftH₂O |
| 50 cmHg | 22.3017 ftH₂O |
| 100 cmHg | 44.6033 ftH₂O |