Pressure
Convert inch of mercury (inHg) to kilopascal (kPa). Pressure is force per unit area. Process engineers move constantly between SI (kPa, bar) and US (psi) units, and between absolute and gauge.
1 inHg = 3.386389 kPa
To convert inch of mercury to kilopascal, multiply the inHg value by 3.386389. To go the other way, divide by 3.386389 (or multiply by 0.2952998).
| inHg | kPa |
|---|---|
| 1 | 3.386389 |
| 2 | 6.772778 |
| 5 | 16.93194 |
| 10 | 33.86389 |
| 25 | 84.65973 |
| 50 | 169.3195 |
| 100 | 338.6389 |
| 250 | 846.5973 |
| 500 | 1693.195 |
| 1000 | 3386.389 |
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 295.2998 inHg is 1000 kPa.
Multiply the value in inHg by 3.386389 to get kPa. For example, 10 inHg = 33.86389 kPa.
1 inHg equals 3.386389 kPa.
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.