Standard Atmospheres to Bars (atm to bar)
1 standard atmosphere equals 1.01325 bars exactly.
How to convert standard atmospheres to bars
To convert standard atmospheres to bars, multiply the number of standard atmospheres by 1.01325. This factor is exact. To go the other way, multiply bars by 0.9869232667 (rounded).
bars = standard atmospheres × 1.01325
Example: 10 standard atmospheres = 10.1325 bars.
About these units
Standard Atmosphere (atm)
Exactly 101,325 pascals, the average pressure of the atmosphere at sea level.
A column of mercury about 76 cm tall was Torricelli's measure of the air, and the standard atmosphere began as exactly that: the pressure of 760 mm of mercury at 0 degrees Celsius under standard gravity. It was used as a reference for physical and chemical properties, and the Celsius scale set 100 degrees as the boiling point of water at that pressure.
In 1954 the 10th CGPM confirmed the standard atmosphere as exactly 1,013,250 dynes per square centimeter, which is 101,325 pascals, a definition that no longer depends on the properties of any substance.
In practice one atmosphere is about 1.01325 bar, 760 mmHg, 14.696 psi or 29.92 inHg, and roughly the pressure of 10.33 meters of water. Chemistry splits on it: until 1982 standard temperature and pressure used 1 atm, but that year IUPAC recommended a standard pressure of exactly 100 kPa instead.
1 standard atmosphere = 101,325 pascals (exactly).
Sources: Wikipedia: Standard atmosphere (unit); Wikipedia: Atmospheric pressure; Wikipedia: Evangelista Torricelli
Bar (bar)
Exactly 100,000 pascals, close to atmospheric pressure at sea level. Used for tire pressure, diving and industrial gauges.
Bar began as a name that meant different things to different people. It comes from the Ancient Greek baros, weight, and from 1793 to 1795 an early metric system used bar for a unit of mass equal to the modern tonne. The pressure bar was introduced by the Norwegian meteorologist Vilhelm Bjerknes, a founder of modern weather forecasting, who defined it as one megadyne per square centimeter. Some earlier writers had used bar for one dyne per square centimeter, a source of confusion.
The bar is a metric unit but not part of the SI, and its official symbol is simply bar, since the old b clashes with the barn and the bit. It has been legally recognized in EU countries since 2004, although NIST deprecates it except for limited use in meteorology.
Its size is handy because 1 bar is slightly less than average sea-level pressure, which is about 1.013 bar. In scuba diving every 10 meters of seawater adds about 1 bar and a full standard tank holds about 200 bar. Tire pressure and turbocharger boost are often quoted in bar outside the US.
1 bar = 100,000 pascals (exactly).
Sources: Wikipedia: Bar (unit); Wikipedia: Atmospheric pressure
Related conversions
- Bars to standard atmospheres (reverse)
- Standard atmospheres to pascals
- Standard atmospheres to kilopascals
- Standard atmospheres to PSI
- Standard atmospheres to hectopascals
- Standard atmospheres to megapascals
- Standard atmospheres to millibars
- Standard atmospheres to torr
- Standard atmospheres to millimeters of mercury
- Standard atmospheres to inches of mercury
- Standard atmospheres to gigapascals
- Standard atmospheres to kilopounds per square inch
- Standard atmospheres to millimeters of water
- Pascals to bars
- Kilopascals to bars
- PSI to bars
- Hectopascals to bars
- Megapascals to bars
- Millibars to bars
- Torr to bars
- Millimeters of mercury to bars
- Inches of mercury to bars
- Gigapascals to bars
- Kilopounds per square inch to bars
- Millimeters of water to bars
See all pressure units.