Convert Torr to Standard Atmospheres
Convert Torr (Torr) to Standard Atmospheres (atm) instantly and accurately.
Conversion Formula
atm = Torr × 0.001315789474
About Torr
The torr is defined as exactly 1/760 of a standard atmosphere ≈ 133.322 Pa - effectively replacing mmHg with an exact definition. Named after Evangelista Torricelli (1608-1647), inventor of the barometer. Vacuum science universally uses torr: rough vacuum 760-1 torr; medium vacuum 1-10⁻³ torr; high vacuum 10⁻³-10⁻⁷ torr; ultra-high vacuum below 10⁻⁹ torr. UHV systems for surface science, particle accelerator beam tubes, and space simulation chambers reach 10⁻¹¹-10⁻¹² torr. 1 torr = 133.322 Pa.
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
| Torr (Torr) | Standard Atmospheres (atm) |
|---|---|
| 1 Torr | 0.00131579 atm |
| 2 Torr | 0.00263158 atm |
| 5 Torr | 0.00657895 atm |
| 10 Torr | 0.0131579 atm |
| 25 Torr | 0.0328947 atm |
| 50 Torr | 0.0657895 atm |
| 100 Torr | 0.131579 atm |