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Pressure
MmHg to Atmospheres
Convert mmHg (mmHg) to atmospheres (atm). Type a value below to see the result update instantly. Reference table and formula included.
Calculator
1 mmHg = 0.001316 atm
MmHg to Atmospheres Conversion Table
Common values, ready to copy:
| mmHg | atmospheres |
|---|---|
| 1 mmHg | 0.001316 atm |
| 2 mmHg | 0.002632 atm |
| 5 mmHg | 0.006579 atm |
| 10 mmHg | 0.013158 atm |
| 25 mmHg | 0.032895 atm |
| 50 mmHg | 0.065789 atm |
| 100 mmHg | 0.131579 atm |
| 1,000 mmHg | 1.3158 atm |
Formula
atmospheres = mmHg × 1.31578584e-3
Pressure is force per area. 1 atm = 101.325 kPa = 14.696 psi = 760 mmHg. Bar is a metric working unit close to atmospheric pressure (1 bar = 100 kPa).
About MmHg and Atmospheres
MmHg (mmHg): Millimeters of mercury; the pressure exerted by a column of mercury that height; a torr is essentially identical (1 mmHg ≈ 1 torr to within 1 part in 7 million). Common uses: Blood pressure (systolic over diastolic, in mmHg), vacuum systems, barometric pressure in some medical and scientific contexts.
Atmospheres (atm): Originally the average atmospheric pressure at sea level (101,325 Pa exactly); replaced in scientific work by the kilopascal but still used in chemistry and physiology. Common uses: Chemistry (gas-phase reactions, vapor pressure references), diving (depth pressure in atmospheres of seawater), and some compressed-gas contexts.
How the conversion works
Pressure is force per area. 1 atm = 101.325 kPa = 14.696 psi = 760 mmHg. Bar is a metric working unit close to atmospheric pressure (1 bar = 100 kPa).
The exact relationship is atmospheres = mmHg × 1.31578584e-3, which the calculator at the top of this page applies in both directions. Type into either field and the other updates immediately.
When this conversion matters
Converting between mmHg and atmospheres comes up wherever pressure measurements move between systems — from one country's conventions to another's, from a scientific reference to a practical specification, or from one industry's working unit to another's. The calculator and reference table above cover the everyday range; for unusual values you can type any number into either field.