Convert Inches of Water to Centimeters of Mercury
Convert Inches of Water (inH₂O) to Centimeters of Mercury (cmHg) instantly and accurately.
Conversion Formula
cmHg = inH₂O × 0.1868320204
About Inches of Water
One inch of water column (inH₂O or in WC) = pressure from 1 inch of fresh water at standard gravity ≈ 249.09 Pa. The standard unit for low-pressure measurement in US HVAC and plumbing: ductwork static pressure, fan performance, filter ratings, and gas appliance manifold pressures are all specified in inches WC. Household natural gas supply pressure is typically 7 in WC (0.25 psi). Blower door tests for building air-tightness use 50 Pa ≈ 0.2 in WC test pressure. 1 inH₂O = 249.089 Pa.
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.
Quick Reference Table
| Inches of Water (inH₂O) | Centimeters of Mercury (cmHg) |
|---|---|
| 1 inH₂O | 0.186832 cmHg |
| 2 inH₂O | 0.373664 cmHg |
| 5 inH₂O | 0.93416 cmHg |
| 10 inH₂O | 1.86832 cmHg |
| 25 inH₂O | 4.6708 cmHg |
| 50 inH₂O | 9.3416 cmHg |
| 100 inH₂O | 18.6832 cmHg |