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Pressure
Atmospheres to InHg
Convert atmospheres (atm) to inHg (inHg). Type a value below to see the result update instantly. Reference table and formula included.
Calculator
1 atm = 29.9212 inHg
Atmospheres to InHg Conversion Table
Common values, ready to copy:
| atmospheres | inHg |
|---|---|
| 1 atm | 29.9212 inHg |
| 2 atm | 59.8425 inHg |
| 5 atm | 149.61 inHg |
| 10 atm | 299.21 inHg |
| 25 atm | 748.03 inHg |
| 50 atm | 1496.06 inHg |
| 100 atm | 2992.12 inHg |
| 1,000 atm | 29921.24 inHg |
Formula
inHg = atmospheres × 2.99212436e+1
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 Atmospheres and InHg
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.
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.
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 inHg = atmospheres × 2.99212436e+1, 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 atmospheres and inHg 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.