Convert Millimeters of Mercury to Hectopascals
Convert Millimeters of Mercury (mmHg) to Hectopascals (hPa) instantly and accurately.
Conversion Formula
hPa = mmHg × 1.333223874
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 Hectopascals
A hectopascal (hPa) = 100 Pa = 1 mbar - the WMO-official SI-compatible meteorological pressure unit since 1986, replacing millibar with no numerical change. All modern surface observations (METAR, SYNOP), digital barometers, aviation weather, and weather apps report in hPa. QNH altimeter settings outside North America are in hPa. ICAO standard sea-level pressure is 1013.25 hPa. Continental high-pressure record exceeds 1084 hPa; Typhoon Tip (1979) holds the low record at ~870 hPa. 1 hPa = 100 Pa.
Quick Reference Table
| Millimeters of Mercury (mmHg) | Hectopascals (hPa) |
|---|---|
| 1 mmHg | 1.33322 hPa |
| 2 mmHg | 2.66645 hPa |
| 5 mmHg | 6.66612 hPa |
| 10 mmHg | 13.3322 hPa |
| 25 mmHg | 33.3306 hPa |
| 50 mmHg | 66.6612 hPa |
| 100 mmHg | 133.322 hPa |