Convert Pascals to Millimeters of Water
Convert Pascals (Pa) to Millimeters of Water (mmH₂O) instantly and accurately.
Conversion Formula
mmH₂O = Pa × 0.1019716213
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.
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.
Quick Reference Table
| Pascals (Pa) | Millimeters of Water (mmH₂O) |
|---|---|
| 1 Pa | 0.101972 mmH₂O |
| 2 Pa | 0.203943 mmH₂O |
| 5 Pa | 0.509858 mmH₂O |
| 10 Pa | 1.01972 mmH₂O |
| 25 Pa | 2.54929 mmH₂O |
| 50 Pa | 5.09858 mmH₂O |
| 100 Pa | 10.1972 mmH₂O |