Convert pressure units — Pascal, bar, PSI, atm, Torr, mmHg.
| Unit | Name | Value |
|---|---|---|
| Pa | Pascal | 100000 |
| kPa | Kilopascal | 100 |
| atm | Atmosphere | 0.98692327 |
| psi | PSI | 14.503768 |
| Torr | Torr / mmHg | 750.06376 |
| inHg | Inch of Mercury | 29.529971 |
Formula: Atmosphere = Bar × 0.9869
Multiply any bar value by 0.9869 to get atmosphere.
Reverse: Bar = Atmosphere × 1.013
Common bar values — factor: 1 bar = 0.9869 atm
| Bar (bar) | Atmosphere (atm) | Context |
|---|---|---|
| 0.001 bar | 0.0009869 atm | 0.1 kPa |
| 0.01 bar | 0.009869 atm | 1 kPa |
| 0.1 bar | 0.09869 atm | 10 kPa |
| 1 bar | 0.9869 atm | 100 kPa / ~1 atm |
| 1.013 bar | 1 atm | 1 standard atm |
| 2 bar | 1.974 atm | 29 psi / car tire |
| 5 bar | 4.935 atm | 72 psi |
| 10 bar | 9.869 atm | 145 psi |
| 100 bar | 98.69 atm | 1,450 psi |
| 200 bar | 197.4 atm | Scuba tank |
| 300 bar | 296.1 atm | High-pressure system |
| 500 bar | 493.5 atm | 5,000 psi |
| 1,000 bar | 986.9 atm | 10,000 psi |
| 0.06895 bar | 0.06805 atm | 1 psi |
| 0.001333 bar | 0.001316 atm | 1 mmHg |
Bar × 0.9869 = atm. Almost 1:1.
Only 1.3% difference — good rough approximation.
atm × 1.01325 = bar.
Monitors dive cylinder pressure in bar — standard in most of the world (200–300 bar).
Reads surface pressure maps in millibar (1 mbar = 0.001 bar) for weather forecasting.
Designs European hydraulic systems — pumps and actuators are rated in bar.
Controls fermentation vessel pressure (1–3 bar) and carbonation pressures in bar.
Specifies pipeline operating pressures and safety relief settings in bar.
Monitors tire pressure and boost pressure on turbocharged engines in bar.
The bar is a metric unit of pressure equal to exactly 100,000 pascals — very close to standard atmospheric pressure (1 atm = 1.01325 bar). It was introduced in 1909 and is widely used in Europe for weather forecasting, diving, and industrial applications.
Scuba diving cylinders are filled to 200–300 bar. Automotive tire pressure gauges often display in bar across Europe. Industrial compressors and hydraulic systems are commonly rated in bar.
Interesting fact: The millibar (mbar = hPa) is the standard unit for atmospheric pressure in meteorology worldwide. Standard sea-level atmospheric pressure is 1013.25 mbar.
The atmosphere (atm) is defined as exactly 101,325 pascals — the approximate air pressure at sea level. It was originally defined as the average atmospheric pressure at sea level at 45° latitude, and has been a standard reference since the 17th century.
Atmospheres are used in chemistry (gas laws), scuba diving depth calculations (every 10 m of water ≈ 1 additional atm), and as a convenient reference for extreme pressure comparisons.
Interesting fact: Jupiter's atmosphere has pressures exceeding 1,000 atm at depth. Diamond formation in Earth's mantle requires pressures of 45,000–60,000 atm at depths of 150–200 km.
Converting bar to atmosphere is a common task in engineering, medicine, meteorology, and science. Different industries and countries use different pressure units — PSI in the US, bar in Europe, mmHg in medicine, and pascals in physics — making accurate conversion essential for cross-disciplinary work.
Quick reference: 5 bar = 4.935 atm and 10 bar = 9.869 atm. For the reverse: 1 atm = 1.013 bar. The exact factor is 1 bar = 0.9869 atm.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.