Atmosphere (atm)
A unit of pressure equal to the standard atmospheric pressure at sea level
The Atmosphere (atm) is a unit of pressure with a history connected to the study of fluids, gases, and atmospheric phenomena. Evangelista Torricelli's invention of the barometer in 1643 was a landmark in pressure measurement, and subsequent work by Blaise Pascal established the mathematical foundations. The pascal — the SI unit — was named in Pascal's honor when the SI system was formalized. The Atmosphere reflects either the SI tradition or the practical conventions of specific industries that standardized their measurements independently.
Accurate pressure measurement is critical in engineering, science, commerce, and everyday life. Using the correct unit and applying conversions precisely prevents errors that can be costly or dangerous in professional applications.
Conversion Table
| Unit | Symbol | 1 atm = |
|---|---|---|
| Pascal | Pa | 101325 Pa |
| Kilopascal | kPa | 101.325 kPa |
| Bar | bar | 1.01325 bar |
| Pound per Square Inch | psi | 14.6959 psi |
| Millimeters of Mercury | mmHg | 760.002 mmHg |
| Megapascal | MPa | 0.101325 MPa |
| Gigapascal | GPa | 0.000101325 GPa |
| Kilopound per Square Inch | ksi | 0.0146959 ksi |
| Torr | torr | 760.002 torr |
| Inch of Mercury | inHg | 29.9212 inHg |
| Kilogram-force per Square Centimeter | kgf/cm² | 1.03323 kgf/cm² |
Conversions Involving Atmosphere
Pascal → Atmosphere
Pa → atm
Kilopascal → Atmosphere
kPa → atm
Bar → Atmosphere
bar → atm
Atmosphere → Pascal
atm → Pa
Atmosphere → Kilopascal
atm → kPa
Atmosphere → Bar
atm → bar
Atmosphere → Pound per Square Inch
atm → psi
Atmosphere → Millimeters of Mercury
atm → mmHg
Atmosphere → Megapascal
atm → MPa
Atmosphere → Gigapascal
atm → GPa
Atmosphere → Kilopound per Square Inch
atm → ksi
Atmosphere → Torr
atm → torr
Atmosphere → Inch of Mercury
atm → inHg
Atmosphere → Kilogram-force per Square Centimeter
atm → kgf/cm²
Pound per Square Inch → Atmosphere
psi → atm
Millimeters of Mercury → Atmosphere
mmHg → atm
Megapascal → Atmosphere
MPa → atm
Gigapascal → Atmosphere
GPa → atm
Kilopound per Square Inch → Atmosphere
ksi → atm
Torr → Atmosphere
torr → atm
Inch of Mercury → Atmosphere
inHg → atm
Kilogram-force per Square Centimeter → Atmosphere
kgf/cm² → atm
Common Uses of the Atmosphere
- •Automotive — inflating tires to manufacturer-specified pressures
- •Weather reporting — tracking barometric pressure for forecasting
- •Hydraulic systems — designing and operating fluid power equipment
- •Scuba diving — calculating safe dive depths based on partial pressures
- •Medical — measuring blood pressure and calibrating medical equipment
Did You Know?
The deepest point in the ocean — the Challenger Deep in the Mariana Trench — has a water pressure of approximately 110 MPa, or about 1,086 times standard atmospheric pressure. The Atmosphere is one of several units used to express pressures across this extraordinary range.