mmH2O to PSI Converter
Pressure · unit-converter
Convert mmH2O to PSI with a fixed input and output unit, step-by-step formula line, and reference tables. All calculations bridge through pascal with fixed definitions (standard atmosphere = 101,325 Pa; torr and mmHg = atm/760; plus industrial/manometer units like kgf/cm², inHg, inH2O, and mmH2O).
About mmH2O
Millimeters of water column (mmH2O) is used for very low differential pressure in instrumentation and ventilation.
About PSI
Pounds-force per square inch (PSI) is common for tires, hydraulics, and US industrial equipment.
How to convert millimeter of water (mmh2o, 4 °c) to psi
1 mmh2o equals 0.0014223343307120308 psi in this tool (via pascal):
1 mmh2o = (9.80665 Pa ÷ 6894.757293168 Pa) psi = 0.0014223343307120308 psi
Each mmh2o carries 9.80665 Pa and each psi 6894.757293168 Pa, so one mmh2o equals 9.80665 ÷ 6894.757293168 psi.
Let p(mmh2o) be pressure in mmH2O (mmh2o), and p(psi) in PSI (psi). Then:
p(psi) = p(mmh2o) × (9.80665 / 6894.757293168)
Equivalently, divide by how many mmh2o fit into one psi (Pa per psi divided by Pa per mmh2o):
p(psi) = p(mmh2o) ÷ 703.0695796391225
Examples
Example #1: Convert 1 mmh2o to psi
1 mmh2o = 1 mmh2o × (9.80665/6894.757293168) psi = 0.0014223343 psi
1 mmh2o = 1 mmh2o ÷ 703.0695796391225 = 0.0014223343 psi
1 mmh2o × (9.80665/6,894.757293168) = 0.001422 psi
Example #2: Convert 10 mmh2o to psi
10 mmh2o = 10 mmh2o × (9.80665/6894.757293168) psi = 0.0142233433 psi
10 mmh2o = 10 mmh2o ÷ 703.0695796391225 = 0.0142233433 psi
10 mmh2o × (9.80665/6,894.757293168) = 0.014223 psi
Summary
To convert mmH2O to PSI, multiply the value in mmh2o by (9.80665 Pa per mmh2o) / (6894.757293168 Pa per psi). Equivalently: value_psi = value_mmh2o × (9.80665 / 6894.757293168). Numerically, 1 mmh2o equals 0.0014223343307120308 psi.
Relationship context
Both mmH2O and PSI are converted by fixed multiples of the pascal. Multiplying by (Pa per mmh2o) ÷ (Pa per psi) gives the same result as passing through pascal, keeping bar, atm, PSI, kPa, hPa, torr, and mmHg consistent on the hub.
Conversion tables
| mmH2O (mmh2o) | PSI (psi) |
|---|---|
| 0.1 | 0.0001422334 |
| 1 | 0.0014223343 |
| 2 | 0.0028446687 |
| 3 | 0.004267003 |
| 4 | 0.0056893373 |
| 5 | 0.0071116717 |
| 6 | 0.008534006 |
| 7 | 0.0099563403 |
| 8 | 0.0113786746 |
| 9 | 0.012801009 |
| mmH2O (mmh2o) | PSI (psi) |
|---|---|
| 10 | 0.0142233433 |
| 20 | 0.0284466866 |
| 30 | 0.0426700299 |
| 40 | 0.0568933732 |
| 50 | 0.0711167165 |
| 60 | 0.0853400598 |
| 70 | 0.0995634031 |
| 80 | 0.1137867465 |
| 90 | 0.1280100898 |
| 100 | 0.1422334331 |