Inches of water to psi
Type a value in inches of water to see it in psi straight away, or type in the second box to convert back.
Loading the tool…
Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Type the value in the inches of water box.
- Read the result in psi as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
psi = inH₂O × 0.036127292
Multiply the value in inches of water by 0.036127292 to get psi.
Example
To convert 25 inH₂O to psi: 25 × 0.036127292 = 0.903182 psi.
Conversion table
| Inches of water (inH₂O) | Psi (psi) |
|---|---|
| 1 | 0.0361273 |
| 2 | 0.0722546 |
| 3 | 0.108382 |
| 5 | 0.180636 |
| 10 | 0.361273 |
| 20 | 0.722546 |
| 25 | 0.903182 |
| 50 | 1.80636 |
| 100 | 3.61273 |
| 250 | 9.03182 |
| 500 | 18.0636 |
| 1,000 | 36.1273 |
About the units
- Inch of water
- The pressure of a one inch water column at the conventional density 1000 kg/m³ and standard gravity: 249.08891 Pa. Used for HVAC ducts and air flow.
- Psi
- One pound-force per square inch, about 6894.757 pascals from the exact definitions of the pound, inch and standard gravity.
Limits and caveats
- Results are rounded for display and computed with the browser's floating point precision (about 15 significant digits).
- Both unit factors are exact by their official definitions.
Questions about this tool
How many psi are in one inch of water?
1 inH₂O = 0.0361273 psi exactly.
How do I convert inches of water to psi?
Use psi = inH₂O × 0.036127292. For example, 25 inH₂O = 0.903182 psi.
How many inches of water are in one psi?
1 psi = 27.6799 inH₂O.
What is the difference between gauge and absolute pressure?
Gauge pressure is measured from the surrounding air pressure, while absolute pressure starts from a perfect vacuum. These converters change the unit only, so a gauge reading stays a gauge reading.
Are torr and mmHg the same?
Almost. One torr is 101325/760 Pa, about 133.322368 Pa, and one conventional mmHg is 133.322387 Pa, a difference of less than one part per million. For everyday use you can treat them as equal.