Convert Bars to Standard Atmospheres

Convert Bars (bar) to Standard Atmospheres (atm) instantly and accurately.

Bars (bar)
Standard Atmospheres (atm)

Conversion Formula

atm = bar × 0.9869232667

About Bars

A bar = exactly 100,000 Pa ≈ 0.987 atm - the world standard for industrial pressure outside North America. Hydraulic systems, pneumatic equipment, gas cylinders, dive computers, and tyre gauges in Europe and Asia use bar. Scuba diving: +1 bar per 10 m depth; at 40 m recreational limit = 5 bar absolute. European tyre pressure labels show bar alongside kPa. Industrial processes: steam at 10-50 bar; high-pressure reactors 100-300 bar; water-jet cutting 1,000-4,000 bar. 1 bar = 100,000 Pa = 14.504 psi.

About Standard Atmospheres

The standard atmosphere (atm) = exactly 101,325 Pa - defined by the 10th CGPM (1954) as the reference air pressure at sea level. Used to define STP (0°C and 1 atm) for gas law and thermochemistry. Chemical equilibrium constants (Kp), Henry's law solubility, and thermodynamic tables are tabulated at 1 atm. ISA aviation standard: sea-level 1 atm / 15°C, pressure halving every ~5.5 km. Diving physics: +1 atm per 10 m depth (fresh water) so 30 m = 4 atm absolute. Diamond formation in Earth's mantle: ~50,000 atm. 1 atm = 101,325 Pa.

Quick Reference Table

Bars (bar)Standard Atmospheres (atm)
1 bar0.986923 atm
2 bar1.97385 atm
5 bar4.93462 atm
10 bar9.86923 atm
25 bar24.6731 atm
50 bar49.3462 atm
100 bar98.6923 atm

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