Convert Standard Atmospheres to Bars
Convert Standard Atmospheres (atm) to Bars (bar) instantly and accurately.
Conversion Formula
bar = atm × 1.01325
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.
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.
Quick Reference Table
| Standard Atmospheres (atm) | Bars (bar) |
|---|---|
| 1 atm | 1.01325 bar |
| 2 atm | 2.0265 bar |
| 5 atm | 5.06625 bar |
| 10 atm | 10.1325 bar |
| 25 atm | 25.3313 bar |
| 50 atm | 50.6625 bar |
| 100 atm | 101.325 bar |