Inches of water to pascals
Type a value in inches of water to see it in pascals straight away, or type in the second box to convert back.
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How to use it
- Type the value in the inches of water box.
- Read the result in pascals as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
Pa = inH₂O × 249.08891
Multiply the value in inches of water by 249.08891 to get pascals.
Example
To convert 25 inH₂O to pascals: 25 × 249.08891 = 6,227.22 Pa.
Conversion table
| Inches of water (inH₂O) | Pascals (Pa) |
|---|---|
| 1 | 249.089 |
| 2 | 498.178 |
| 3 | 747.267 |
| 5 | 1,245.44 |
| 10 | 2,490.89 |
| 20 | 4,981.78 |
| 25 | 6,227.22 |
| 50 | 12,454.4 |
| 100 | 24,908.9 |
| 250 | 62,272.2 |
| 500 | 124,544 |
| 1,000 | 249,089 |
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.
- Pascal
- The SI unit of pressure, equal to a force of one newton acting on one square meter.
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 pascals are in one inch of water?
1 inH₂O = 249.089 Pa exactly.
How do I convert inches of water to pascals?
Use Pa = inH₂O × 249.08891. For example, 25 inH₂O = 6,227.22 Pa.
How many inches of water are in one pascal?
1 Pa = 0.00401463 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.