Convert Standard Atmospheres (atm) to Bar
1 standard atmosphere equals 1.01325 bar.
Standard Atmosphere to Bar Converter
How to Convert Standard Atmosphere to Bar
1 standard atmosphere = 1.01325 bar
Bar = Standard Atmosphere × 1.01325
Example: 1 atm × 1.01325 = 1.01325 bar
Reverse Conversion
To convert bar back to standard atmospheres:
- Remember, 1 bar equals 0.986923 standard atmospheres.
- To convert 1.01325 bar to atm, multiply
1.01325 x 0.986923, resulting in1 atm.
Common Standard Atmosphere to Bar Conversions
| Standard Atmosphere | Bar | Actions |
|---|---|---|
| 1 standard atmosphere | 1.01325 bar | |
| 2 standard atmospheres | 2.0265 bar |
| Standard Atmosphere | Bar | Actions |
|---|---|---|
| 5 standard atmospheres | 5.06625 bar | |
| 10 standard atmospheres | 10.1325 bar |
Standard atmospheres to bar Conversion Table
Reference table with common standard atmospheres to bar conversions. All values calculated with high precision.
Standard Atmospheres to Bar Table
0.0001 to 12
Standard Atmospheres to Bar Table
1 to 100000
Bar to Standard Atmospheres Table
0.001 to 5
Bar to Standard Atmospheres Table
10 to 1000000
Definition of Standard Atmosphere
Atmosphere: Standard Atmospheric Pressure
The standard atmosphere (atm) is a unit of pressure defined as exactly 101,325 pascals. It represents the typical atmospheric pressure at sea level under standard conditions. The atmosphere is commonly used as a reference point for pressure measurements and is particularly important in chemistry, physics, and meteorology for defining standard conditions.
Conversions to Other Units of Measurement:
- Pascal (Pa): 1 atmosphere equals exactly 101,325 pascals. This is the definition of the standard atmosphere.
- Bar: 1 atmosphere equals exactly 1.01325 bar. The bar was designed to be close to atmospheric pressure. For example, 2 atm equals 2.0265 bar.
- PSI: 1 atmosphere equals approximately 14.6959 psi. This is a fundamental conversion for many applications. Standard atmospheric pressure is often approximated as 14.7 psi.
- Torr: 1 atmosphere equals exactly 760 torr. This relationship comes from the original definition of the torr based on mercury column height.
- Millibar (mbar): 1 atmosphere equals exactly 1013.25 millibar. This is commonly used in meteorology for weather maps.
The atmosphere provides an intuitive reference for pressure, being directly related to the air pressure we experience daily at sea level.
- Definition
- Standard unit of atmospheric pressure defined as exactly 101,325 pascals.
- Exact factor
- 1 atm = 101,325 Pa (exact)
- Common equivalents
- 1 atm = 760 torr (exact by definition)
- 1 atm = 1.01325 bar (exact)
- 1 atm ≈ 14.6959 psi
- Sources
Definition of Bar
Bar: A Widely Used Pressure Unit
The bar is a metric unit of pressure defined as exactly 100,000 pascals (100 kPa). While not an SI unit, it is accepted for use with the SI and is widely used in meteorology, engineering, and industry. The bar is particularly convenient because standard atmospheric pressure (1 atm) is approximately equal to 1 bar (actually 1.01325 bar).
Conversions to Other Units of Measurement:
- Pascal (Pa): 1 bar equals exactly 100,000 pascals. This conversion is used when working with SI units. For example, 2 bar equals 200,000 Pa or 200 kPa.
- PSI (Pound per Square Inch): 1 bar equals approximately 14.5038 psi. This is one of the most common conversions in industrial applications. For example, a tire pressure of 2.5 bar equals approximately 36.3 psi.
- Atmosphere (atm): 1 bar equals approximately 0.986923 atm. Standard atmospheric pressure (1 atm) equals 1.01325 bar.
- Kilopascal (kPa): 1 bar equals exactly 100 kPa. This conversion is straightforward and commonly used in engineering. For example, 3.5 bar equals 350 kPa.
- Millibar (mbar): 1 bar equals exactly 1,000 millibar. Millibars are commonly used in meteorology for atmospheric pressure measurements.
The bar is valued for its practical convenience, being close to atmospheric pressure while having a simple relationship with SI units.
- Definition
- Metric pressure unit equal to exactly 100,000 pascals.
- Exact factor
- 1 bar = 100,000 Pa (exact); 1 bar = 10⁵ Pa
- Common equivalents
- 1 bar = 1,000 mbar (exact)
- 1 bar ≈ 14.50377 psi
- 1 bar ≈ 0.986923 atm
- Sources
About the Standard Atmosphere
Facts & Uses
- 1 atm = 101,325 Pa exactly — the standard reference for sea-level atmospheric pressure, defined by the 10th CGPM in 1954.
- Used as a reference pressure in chemistry, physics, and meteorology. Many gas calculations use atm as the unit of choice.
- Defines standard temperature and pressure (STP) in older chemistry conventions: 0 °C and 1 atm. (IUPAC since 1982 uses 100 kPa instead.)
- Reference for scuba and diving tables: 1 atm of pressure increase for every 10 m of seawater (or 33 ft).
Curiosities
- The standard atmosphere is an arbitrary reference — actual sea-level pressure varies daily by ±50 hPa based on weather systems.
- The 10th CGPM (1954) chose 101,325 Pa exactly to align with the historical definition based on a 760 mm column of mercury at 0 °C and standard gravity.
- The pressure at the top of Mount Everest is about 0.33 atm (33.7 kPa) — only one-third of sea level, which is why supplemental oxygen is essential above 8000 m.
- Approximate equivalents: 1 atm = 14.696 psi = 1.01325 bar = 760 mmHg = 760 torr.
Sources
About the Bar
Facts & Uses
- 1 bar = 100,000 Pa = 100 kPa exactly. Defined in 1909 by Vilhelm Bjerknes as a convenient meteorological unit close to atmospheric pressure.
- Standard for tire pressure in many European countries (~2.0-2.5 bar for cars), compressed air systems, and water pressure.
- Common in diving (1 bar per 10 m of seawater depth), brewing (espresso extraction at 9 bar), and scuba tanks (200-300 bar fill pressure).
- Weather use: millibars (mbar) = 1/1000 bar = hectopascals (hPa). 1013 mbar = standard sea level pressure.
Curiosities
- The bar is not part of the SI, but is accepted for use with the SI system because of its convenient scale and historical adoption in meteorology.
- The name comes from the Greek "baros" (βάρος) meaning "weight" — also the root of "barometer" and "barometric pressure".
- Atmospheric pressure varies from a record low of 870 mbar (Typhoon Tip, 1979) to a record high of 1085 mbar (Mongolia, 2001).
- Approximate equivalents: 1 bar = 14.504 psi = 0.987 atm = 750 mmHg.
Sources
Frequently Asked Questions
How many bar are in one standard atmosphere?
One standard atmosphere equals 1.01325 bar. To convert, multiply the standard atmosphere value by 1.01325. For the reverse, divide the bar value by 1.01325 (or multiply by 0.986923).
What is 1 standard atmosphere in bar?
1 standard atmosphere = 1.0133 bar. This is one of the most commonly searched conversions for this pair.
How precise is the standard atmosphere-to-bar conversion?
The factor 1.01325 is accurate to 6 significant figures, derived from international measurement standards. Our calculator uses full precision internally.
Looking for the reverse? Convert Bar to Standard Atmosphere
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