Atmospheres (atm) to Millimeters of mercury (mmHg) Conversion
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
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 (atm) | Millimeters of mercury (mmHg) |
|---|---|
| 0.1 atm | 76.00 mmHg |
| 1 atm | 760.00 mmHg |
| 2 atm | 1,520.00 mmHg |
| 3 atm | 2,280.00 mmHg |
| 5 atm | 3,800.00 mmHg |
| 10 atm | 7,599.9999 mmHg |
| 20 atm | 15,199.9998 mmHg |
| 30 atm | 22,799.9997 mmHg |
| 50 atm | 37,999.9995 mmHg |
| 100 atm | 75,999.9991 mmHg |
| 1000 atm | 759,999.991 mmHg |
Frequently Asked Questions (FAQ)
How many millimeters of mercury are in 1 atmospheres?
1 atmospheres (atm) is exactly 760.000 millimeters of mercury (mmHg).
How do I convert atmospheres to millimeters of mercury?
Multiply the value in atmospheres by 760.000 to get the result in millimeters of mercury. Or use the converter above — type any number and see the result instantly.