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Pressure
InHg to Atmospheres
Convert inHg (inHg) to atmospheres (atm). Type a value below to see the result update instantly. Reference table and formula included.
Calculator
1 inHg = 0.033421 atm
InHg to Atmospheres Conversion Table
Common values, ready to copy:
| inHg | atmospheres |
|---|---|
| 1 inHg | 0.033421 atm |
| 2 inHg | 0.066842 atm |
| 5 inHg | 0.167105 atm |
| 10 inHg | 0.334211 atm |
| 25 inHg | 0.835527 atm |
| 50 inHg | 1.6711 atm |
| 100 inHg | 3.3421 atm |
| 1,000 inHg | 33.4211 atm |
Formula
atmospheres = inHg × 3.34210708e-2
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 InHg and Atmospheres
InHg (inHg): Inches of mercury, the imperial equivalent of mmHg; 1 inHg = 25.4 mmHg by definition. Common uses: US weather reports (atmospheric pressure in inches of mercury, standard sea-level pressure ≈ 29.92 inHg), US aviation altimeter settings, and some US vacuum-system 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 = inHg × 3.34210708e-2, 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 inHg 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.