Convert pressure units — Pascal, bar, PSI, atm, Torr, mmHg.
| Unit | Name | Value |
|---|---|---|
| Pa | Pascal | 101325 |
| kPa | Kilopascal | 101.325 |
| bar | Bar | 1.01325 |
| psi | PSI | 14.695943 |
| Torr | Torr / mmHg | 760.0021 |
| inHg | Inch of Mercury | 29.921244 |
Formula: Bar = Atmosphere × 1.013
Multiply any atmosphere value by 1.013 to get bar.
Reverse: Atmosphere = Bar × 0.9869
Common atmosphere values — factor: 1 atm = 1.013 bar
| Atmosphere (atm) | Bar (bar) | Context |
|---|---|---|
| 0.001 atm | 0.001013 bar | Vacuum |
| 0.01 atm | 0.01013 bar | High vacuum |
| 0.1 atm | 0.1013 bar | Mountain top |
| 0.5 atm | 0.5066 bar | Half atmosphere |
| 1 atm | 1.013 bar | Sea level |
| 2 atm | 2.026 bar | 10 m water depth |
| 5 atm | 5.066 bar | 40 m depth |
| 10 atm | 10.13 bar | 90 m depth |
| 50 atm | 50.66 bar | 500 m depth |
| 100 atm | 101.3 bar | 1 km depth |
| 500 atm | 506.6 bar | 5 km depth |
| 1,000 atm | 1,013 bar | 10 km depth |
| 5,000 atm | 5,066 bar | Deep mantle |
| 1e+04 atm | 1.013e+04 bar | Very deep mantle |
| 5e+04 atm | 5.066e+04 bar | Diamond formation |
Atm × 1.01325 = bar. Very close to 1:1.
They differ by only 1.3% — nearly identical for estimates.
bar × 0.9869 = atm.
Uses atmospheres in gas law calculations (PV = nRT) and solubility studies.
Calculates dive depth pressure (every 10 m adds ~1 atm) for dive tables.
Designs diamond anvil cell experiments measuring pressure in thousands of atm.
Specifies autoclave and reactor operating pressures relative to atm.
Estimates metamorphic rock formation pressures in kbar (thousands of atm).
Plans saturation diving operations using atm for depth-pressure calculations.
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.
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.
Converting atmosphere to bar 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 atm = 5.066 bar and 10 atm = 10.13 bar. For the reverse: 1 bar = 0.9869 atm. The exact factor is 1 atm = 1.013 bar.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.