Convert Millimeters of Mercury to Pounds per Square Inch
Convert Millimeters of Mercury (mmHg) to Pounds per Square Inch (psi) instantly and accurately.
Conversion Formula
psi = mmHg × 0.01933677746
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.
About Pounds per Square Inch
One pound per square inch (psi) ≈ 6,894.76 Pa - the dominant pressure unit in US industry and consumer products. Car tyres: 32-36 psi; truck tyres 80-120 psi; bicycle road tyres 80-130 psi. Home water supply: 40-80 psi; residential maximum 80 psi per plumbing code. Compressed air tools: 90-150 psi. Steam autoclave sterilisation: 15-30 psi. The distinction between gauge (psig) and absolute (psia) pressure is critical: gauge pressure is relative to ambient; absolute = gauge + ~14.696 psi. 1 psi = 6,894.76 Pa.
Quick Reference Table
| Millimeters of Mercury (mmHg) | Pounds per Square Inch (psi) |
|---|---|
| 1 mmHg | 0.0193368 psi |
| 2 mmHg | 0.0386736 psi |
| 5 mmHg | 0.0966839 psi |
| 10 mmHg | 0.193368 psi |
| 25 mmHg | 0.483419 psi |
| 50 mmHg | 0.966839 psi |
| 100 mmHg | 1.93368 psi |