Pressure
Convert pound per square inch (psi) to millimetre of mercury (mmHg). 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 = 51.71492 mmHg
To convert pound per square inch to millimetre of mercury, multiply the psi value by 51.71492. To go the other way, divide by 51.71492 (or multiply by 0.01933678).
| psi | mmHg |
|---|---|
| 1 | 51.71492 |
| 2 | 103.4298 |
| 5 | 258.5746 |
| 10 | 517.1492 |
| 25 | 1292.873 |
| 50 | 2585.746 |
| 100 | 5171.492 |
| 250 | 12928.73 |
| 500 | 25857.46 |
| 1000 | 51714.92 |
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 7500.616 mmHg.
Multiply the value in psi by 51.71492 to get mmHg. For example, 10 psi = 517.1492 mmHg.
1 psi equals 51.71492 mmHg.
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.