inHg
Units & Measurements abbreviation · Engineering Unit
| Stands for | Inches of mercury |
|---|---|
| Categories | Units & Measurements |
inHg stands for Inches of mercury, an engineering unit abbreviation.
Pressure unit used in US weather reports and North American aviation altimeter settings, based on the height of mercury in a barometer. Standard sea-level pressure is 29.92 inHg.
Example: Altimeter setting is 29.87 inHg; winds 270 at 12 knots.
Usage notes
One inHg equals about 33.86 hPa. US and Canadian pilots set altimeters in inches of mercury, while most other countries use hectopascals. Readings above about 30.20 inHg usually accompany fair weather. Vacuum gauges on engines and HVAC equipment also read in inHg, with a perfect vacuum near 29.92 inches.