Pressure
Convert pound per square inch (psi) to inch of mercury (inHg). Pressure is force per unit area. Process engineers move constantly between SI (kPa, bar) and US (psi) units, and between absolute and gauge.
1 psi = 2.03602 inHg
To convert pound per square inch to inch of mercury, multiply the psi value by 2.03602. To go the other way, divide by 2.03602 (or multiply by 0.4911542).
| psi | inHg |
|---|---|
| 1 | 2.03602 |
| 2 | 4.072041 |
| 5 | 10.1801 |
| 10 | 20.3602 |
| 25 | 50.90051 |
| 50 | 101.801 |
| 100 | 203.602 |
| 250 | 509.0051 |
| 500 | 1018.01 |
| 1000 | 2036.02 |
Line and vessel ratings, pump discharge heads, and relief set points are all specified in pressure units — usually psi or barg in the field and kPa in calculations.
Always track whether a value is absolute or gauge: 0 barg equals about 101.3 kPa absolute, and mixing the two is a common and costly error.
Worked example. A pressure of 145.0377 psi is 295.2998 inHg.
Multiply the value in psi by 2.03602 to get inHg. For example, 10 psi = 20.3602 inHg.
1 psi equals 2.03602 inHg.
Line and vessel ratings, pump discharge heads, and relief set points are all specified in pressure units — usually psi or barg in the field and kPa in calculations.