Convert Torr to Millimeters of Mercury
Convert Torr (Torr) to Millimeters of Mercury (mmHg) instantly and accurately.
Conversion Formula
mmHg = Torr × 0.9999998575
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 Millimeters of Mercury
One millimetre of mercury (mmHg) = pressure from 1 mm of mercury at 0°C and standard gravity = 133.322 Pa. Clinical medicine worldwide uses mmHg for blood pressure (normal ~120/80 mmHg) and for gas partial pressures in physiology: arterial O₂ ~95-100 mmHg; CO₂ ~40 mmHg; alveolar O₂ ~104 mmHg. Ophthalmologists measure intraocular pressure in mmHg (normal 10-21; glaucoma risk above 21). Vacuum equipment ratings are also given in mmHg. 760 mmHg = 1 atm. 1 mmHg = 133.322 Pa.
Quick Reference Table
| Torr (Torr) | Millimeters of Mercury (mmHg) |
|---|---|
| 1 Torr | 1 mmHg |
| 2 Torr | 2 mmHg |
| 5 Torr | 5 mmHg |
| 10 Torr | 10 mmHg |
| 25 Torr | 25 mmHg |
| 50 Torr | 50 mmHg |
| 100 Torr | 100 mmHg |