Convert Millimeters of Mercury to Inches of Mercury
Convert Millimeters of Mercury (mmHg) to Inches of Mercury (inHg) instantly and accurately.
Conversion Formula
inHg = mmHg × 0.03937007874
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 Inches of Mercury
One inch of mercury (inHg) ≈ 3,386 Pa - the primary barometric pressure unit in US aviation and meteorology. ASOS weather stations, METARs, and altimeter settings in the US report in inHg. Standard sea-level pressure is 29.92 inHg. Altimeters are set to local QNH in inHg to maintain altitude reference. US barometers for home weather stations display inHg. Typical pressure range: 28.5-31.0 inHg in continental weather systems. Record low: ~25.70 inHg (Typhoon Tip, 1979). 1 inHg = 3,386.39 Pa.
Quick Reference Table
| Millimeters of Mercury (mmHg) | Inches of Mercury (inHg) |
|---|---|
| 1 mmHg | 0.0393701 inHg |
| 2 mmHg | 0.0787402 inHg |
| 5 mmHg | 0.19685 inHg |
| 10 mmHg | 0.393701 inHg |
| 25 mmHg | 0.984252 inHg |
| 50 mmHg | 1.9685 inHg |
| 100 mmHg | 3.93701 inHg |