Inches of mercury to psi
Type a value in inches of mercury to see it in psi 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 mercury 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 = inHg × 0.4911541475
Multiply the value in inches of mercury by 0.4911541475 to get psi.
Example
To convert 25 inHg to psi: 25 × 0.4911541475 = 12.2789 psi.
Conversion table
| Inches of mercury (inHg) | Psi (psi) |
|---|---|
| 1 | 0.491154 |
| 2 | 0.982308 |
| 3 | 1.47346 |
| 5 | 2.45577 |
| 10 | 4.91154 |
| 20 | 9.82308 |
| 25 | 12.2789 |
| 50 | 24.5577 |
| 100 | 49.1154 |
| 250 | 122.789 |
| 500 | 245.577 |
| 1,000 | 491.154 |
About the units
- Inch of mercury
- The pressure of a one inch mercury column at conventional density and standard gravity, about 3386.389 Pa. Common in aviation and US weather reports.
- 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 mercury?
1 inHg = 0.491154 psi exactly.
How do I convert inches of mercury to psi?
Use psi = inHg × 0.4911541475. For example, 25 inHg = 12.2789 psi.
How many inches of mercury are in one psi?
1 psi = 2.03602 inHg.
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.