Convert Bar to Atmospheres
1 bar equals 0.9869232667 atmospheres (atm).
1 bar = 0.9869232667 atm
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk bar to atmosphere converter to paste a column from Excel.
How to Convert Bar to Atmosphere
- 1 bar = 0.9869232667 atm
- 1 atm = 1.01325 bar
- Example: convert 15 bar to atm: 15 bar = 15 × 0.9869232667 atm = 14.803849 atm
Formula
atm = bar × 0.986923266716
or atm = bar ÷ 1.01325
Derivation from SI units:
- 1 bar = 10⁵ Pa (exact, by definition)
- 1 atm = 101 325 Pa (exact, by definition)
- 1 bar = 100000 Pa ÷ 101325 Pa per atm = 0.986923266716 atm
Both units are defined exactly, so the factor is exact. Bar definition: bar; Atmosphere definition: atmosphere.
Worked examples
- 1 bar is 0.9869232667 atm.
1 bar × 0.9869232667 = 0.9869232667 atm - A scuba cylinder at 200 bar holds gas at 197.3846533 atm.
200 bar × 0.9869232667 = 197.3846533 atm
Bar to Atmosphere conversion table
| Bar | Atmospheres (atm) |
|---|---|
| 0.01 bar | 0.009869232667 atm |
| 0.05 bar | 0.04934616334 atm |
| 0.1 bar | 0.09869232667 atm |
| 0.25 bar | 0.2467308167 atm |
| 0.5 bar | 0.4934616334 atm |
| 1 bar | 0.9869232667 atm |
| 1.01325 bar | 1 atm |
| 1.5 bar | 1.4803849 atm |
| 2 bar | 1.973846533 atm |
| 2.5 bar | 2.467308167 atm |
| 3 bar | 2.9607698 atm |
| 4 bar | 3.947693067 atm |
| 5 bar | 4.934616334 atm |
| 6 bar | 5.9215396 atm |
| 7 bar | 6.908462867 atm |
| 8 bar | 7.895386134 atm |
| 10 bar | 9.869232667 atm |
| 12 bar | 11.8430792 atm |
| 16 bar | 15.79077227 atm |
| 20 bar | 19.73846533 atm |
| 25 bar | 24.67308167 atm |
| 40 bar | 39.47693067 atm |
| 100 bar | 98.69232667 atm |
| 200 bar | 197.3846533 atm |
| 300 bar | 296.07698 atm |
Where it's used
Bar and atmospheres are close but not equal. In diving, gas storage and chemistry the 1.3 % difference adds up at high pressures.
Bar to other pressure units
| Conversion | 1 bar equals |
|---|---|
| bar to pascal | 100000 Pa |
| bar to kilopascal | 100 kPa |
| bar to megapascal | 0.1 MPa |
| bar to psi | 14.50377377 psi |
| bar to millibar | 1000 mbar |
| bar to decibar | 10 dbar |
| bar to torr | 750.0616827 Torr |
| bar to millimeter of mercury | 750.0615758 mmHg |
| bar to millimeter of water | 10197.16213 mmH₂O |
| bar to centimeter of water | 1019.716213 cmH₂O |
| bar to inch of water | 401.463076 inH₂O |
| bar to inch of water (60 °F) | 401.864652 inH₂O (60 °F) |
| bar to inch of mercury | 29.5299833 inHg |
| bar to atmosphere | 0.9869232667 atm |
| bar to barye | 1000000 Ba |
Frequently asked questions
Why is the bar not equal to 1 atm?
The bar was chosen as a round metric value (10⁵ Pa); the atmosphere represents mean sea-level pressure (101 325 Pa). 1 bar = 0.9869232667 atm.
How many atmospheres are in 1 bar?
1 bar = 0.9869232667 atm.
How do I convert bar to atmospheres?
Multiply the value in bar by 0.9869232667, or divide it by 1.01325. For example, 15 bar × 0.9869232667 = 14.803849 atm.
Is the bar to atm conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "bar".
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "atmosphere, standard (atm)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Bar to Atmospheres. Retrieved October 17, 2026, from https://scientificconverters.com/pressure/bar-to-atmosphere/
IEEE
Scientific Converters, "Convert Bar to Atmospheres," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/pressure/bar-to-atmosphere/