[1][2] By the barometric formula, 1 bar is roughly the atmospheric pressure on Earth at an altitude of 111 metres at 15 °C.

[2] The US National Institute of Standards and Technology (NIST) deprecates its use except for "limited use in meteorology" and lists it as one of several units that "must not be introduced in fields where they are not presently used".

[4] The International Astronomical Union (IAU) also lists it under "Non-SI units and symbols whose continued use is deprecated".

Between 1793 and 1795, the word bar was used for a unit of mass (equal to the modern tonne) in an early version of the metric system.

In sea water with respect to the gravity variation, the latitude and the geopotential anomaly the pressure can be converted into metres' depth according to an empirical formula (UNESCO Tech.

Many engineers worldwide use the bar as a unit of pressure because, in much of their work, using pascals would involve using very large numbers.

In hydraulic machinery components are rated to the maximum system oil pressure, which is typically in hundreds of bar.