1 atmosphere equals exactly
1,01325 bar
This is the inverse operation compared to the bar → atmospheres conversion. The standard atmosphere (atm) is defined exactly as 101,325 Pa, the value historically used as a reference for average atmospheric pressure at sea level, while the bar is a slightly smaller unit (100,000 Pa).
To convert a measurement from atmospheres to bar, simply multiply the value by 1.01325:
To convert from bar to atmospheres, perform the inverse operation, multiplying by 0.9869:
This conversion is particularly useful in scuba diving, where pressure is often expressed in atmospheres (every 10 meters of depth adds about 1 atm), but technical equipment (compressors, tanks) often reports specifications in bar.