Pressure
Convert standard atmosphere (atm) 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 atm = 759.9999 mmHg
To convert standard atmosphere to millimetre of mercury, multiply the atm value by 759.9999. To go the other way, divide by 759.9999 (or multiply by 0.00131579).
| atm | mmHg |
|---|---|
| 1 | 759.9999 |
| 2 | 1520 |
| 5 | 3799.999 |
| 10 | 7599.999 |
| 25 | 19000 |
| 50 | 37999.99 |
| 100 | 75999.99 |
| 250 | 190000 |
| 500 | 379999.9 |
| 1000 | 759999.9 |
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 9.869233 atm is 7500.616 mmHg.
Multiply the value in atm by 759.9999 to get mmHg. For example, 10 atm = 7599.999 mmHg.
1 atm equals 759.9999 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.