Convert pressure units — pascal, PSI, bar, atmosphere, torr, mmHg and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 inHg | 0.0338639 mbar | |
| 0.01 inHg | 0.338639 mbar | |
| 0.1 inHg | 3.38639 mbar | |
| 1 inHg | 33.8639 mbar | |
| 5 inHg | 169.32 mbar | |
| 10 inHg | 338.639 mbar | |
| 50 inHg | 1693.2 mbar | |
| 100 inHg | 3386.39 mbar | |
| 1000 inHg | 33863.9 mbar |
Formula: Millibar = Inch Hg × 33.86
Multiply any inch hg value by 33.86 to get millibar.
Reverse: Inch Hg = Millibar × 0.02953
Common inch hg values — factor: 1 inHg = 33.86 mbar
| Inch Hg (inHg) | Millibar (mbar) | Context |
|---|---|---|
| 0.01 inHg | 0.3386 mbar | Near vacuum |
| 0.1 inHg | 3.386 mbar | Very low |
| 1 inHg | 33.86 mbar | Low pressure |
| 10 inHg | 338.6 mbar | ~10 inHg |
| 20 inHg | 677.3 mbar | ~20 inHg |
| 25 inHg | 846.6 mbar | Low weather |
| 28 inHg | 948.2 mbar | Hurricane center |
| 29 inHg | 982.1 mbar | Storm low |
| 29.92 inHg | 1,013 mbar | 1 standard atm |
| 30 inHg | 1,016 mbar | Slightly high |
| 31 inHg | 1,050 mbar | High pressure |
| 35 inHg | 1,185 mbar | Very high |
| 50 inHg | 1,693 mbar | ~1.67 atm |
| 100 inHg | 3,386 mbar | ~3.34 atm |
| 1,000 inHg | 3.386e+04 mbar | ~33.4 atm |
1 inHg = 33.86 mbar. Memorize for instant estimates.
Use 33.86 as a quick mental multiplier.
Multiply result by 0.02953 to recover the original inHg value.
Sets altimeter QNH and reads weather ATIS in inHg — standard US aviation.
Reports barometric pressure in inHg for US television and radio weather.
Measures duct static pressure in inches of water column or inHg in US systems.
Checks HVAC system static pressure and duct leakage in inHg.
Logs surface pressure in inHg for propagation prediction and wx stations.
References inHg barometric pressure when using US-spec nautical instruments.
Inches of mercury (inHg) is the pressure unit used in US aviation and weather reporting, defined as the pressure exerted by a 1-inch column of mercury (3,386.39 Pa). It has been standard in US aviation since the early 20th century.
US aviation altimeters are set in inHg (standard: 29.92 inHg). US weather broadcasts report barometric pressure in inHg. HVAC engineers in the US use inHg for duct static pressure measurements.
Interesting fact: Pilots set their altimeter to the local QNH (pressure at sea level) in inHg to ensure their altitude reading is accurate — a difference of 0.1 inHg causes an altimeter error of about 100 feet.
The millibar (mbar) equals 0.001 bar or 100 pascals, and is numerically identical to the hectopascal (hPa). It became the standard unit for surface pressure in international meteorology in the 20th century.
Weather maps and forecasts worldwide use millibars or hectopascals for surface pressure. Standard sea-level pressure is 1013.25 mbar. Hurricanes and typhoons are characterized by very low central pressures — Hurricane Patricia (2015) reached 872 mbar.
Interesting fact: A 1 mbar pressure difference over 111 km (1° latitude) drives a wind of approximately 1 m/s in mid-latitudes, which is why steep pressure gradients produce strong winds.
Converting inch hg to millibar is a common task in engineering, medicine, meteorology, and science. Different industries and countries use different pressure units — PSI in the US, bar in Europe, mmHg in medicine, and pascals in physics — making accurate conversion essential for cross-disciplinary work.
Quick reference: 5 inHg = 169.3 mbar and 10 inHg = 338.6 mbar. For the reverse: 1 mbar = 0.02953 inHg. The exact factor is 1 inHg = 33.86 mbar.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.