Millimeters of mercury (mmHg) to Atmospheres (atm) Conversion
Millimeters of mercury
The millimetre of mercury (mmHg) is a unit of pressure equal to the pressure exerted by a 1 mm column of mercury at 0 °C and standard gravity — approximately 133.322 Pa. It is the universal clinical standard for measuring blood pressure: normal adult blood pressure is approximately 120/80 mmHg (systolic/diastolic). The mmHg is also used in ophthalmology (intraocular pressure, normal ≈ 10–21 mmHg) and respiratory physiology.
Atmospheres
The standard atmosphere (atm) is a unit of pressure defined as exactly 101,325 Pa, representing the approximate mean atmospheric pressure at sea level. It remains in use in chemistry for expressing gas pressures in thermodynamic tables and standard conditions (STP: 0 °C and 1 atm). One atmosphere supports a mercury column of exactly 760 mm — the basis of the mercury barometer invented by Torricelli in 1643. In deep-sea diving, pressure is expressed in atmospheres absolute (ATA).
| Millimeters of mercury (mmHg) | Atmospheres (atm) |
|---|---|
| 0.1 mmHg | 0.00013157894892672 atm |
| 1 mmHg | 0.0013157894892672 atm |
| 2 mmHg | 0.0026315789785344 atm |
| 3 mmHg | 0.0039473684678016 atm |
| 5 mmHg | 0.006578947446336 atm |
| 10 mmHg | 0.013157894892672 atm |
| 20 mmHg | 0.026315789785344 atm |
| 30 mmHg | 0.039473684678016 atm |
| 50 mmHg | 0.06578947446336 atm |
| 100 mmHg | 0.13157894892672 atm |
| 1000 mmHg | 1.3157894892672 atm |