Convert Millimeters of Water to Pascals
Convert Millimeters of Water (mmH₂O) to Pascals (Pa) instantly and accurately.
Conversion Formula
Pa = mmH₂O × 9.80665
About Millimeters of Water
One millimetre of water column (mmH₂O) = pressure from 1 mm of fresh water at standard gravity = exactly 9.80665 Pa. Preferred for very low differential pressures in HVAC: ductwork static pressures, fan curves, filter resistance, and building pressurisation are in mm WC. Gas valve operating pressures are typically 0.5-3 mm WC; clean-room cascade differentials 12-25 mm WC. A domestic gas hob manifold operates at ~20 mm WC on natural gas. Also used in spirometer calibration and hospital oxygen delivery systems. 1 mmH₂O = 9.80665 Pa.
About Pascals
The pascal (Pa) is the SI unit of pressure - 1 N/m², named after Blaise Pascal (1623-1662). Standard sea-level atmosphere ≈ 101,325 Pa. One pascal is very small: roughly the pressure of a single banknote lying flat. Pascal is simultaneously the SI unit for mechanical stress and elastic modulus: structural steel Young's modulus ~200 GPa; rubber shear modulus ~0.5 MPa. Used universally in fluid mechanics, acoustics, atmospheric science, and materials engineering. 1 Pa = 1 N/m².
Quick Reference Table
| Millimeters of Water (mmH₂O) | Pascals (Pa) |
|---|---|
| 1 mmH₂O | 9.80665 Pa |
| 2 mmH₂O | 19.6133 Pa |
| 5 mmH₂O | 49.0332 Pa |
| 10 mmH₂O | 98.0665 Pa |
| 25 mmH₂O | 245.166 Pa |
| 50 mmH₂O | 490.332 Pa |
| 100 mmH₂O | 980.665 Pa |