Millibars to Inches Of Mercury (mbar to inHg)
1 millibar equals 0.0295299833 inches of mercury (rounded).
How to convert millibars to inches of mercury
To convert millibars to inches of mercury, multiply the number of millibars by 0.0295299833. The factor is rounded to 10 significant digits. To go the other way, multiply inches of mercury by 33.8638864 (rounded).
inches of mercury = millibars × 0.0295299833
Example: 10 millibars = 0.295299833 inches of mercury.
About these units
Millibar (mbar)
One thousandth of a bar, equal to one hectopascal. Standard atmospheric pressure is 1,013.25 mbar.
Millibar and hectopascal are the same pressure with different pedigrees. The millibar was introduced alongside the bar by Vilhelm Bjerknes, and meteorologists worldwide adopted it because the values are convenient: a thousandth of a bar puts ordinary air pressure near 1,000. Standard atmospheric pressure is 1,013.25 millibars.
When SI came in, some meteorologists switched to hectopascals, which carry exactly the same numbers. The millibar did not vanish, though. The symbol mb is still common, and Americans know the unit from US hurricane and cyclone reports.
A few readings give the scale. The record-low non-tornadic pressure of 870 hPa in Typhoon Tip in 1979 equals 870 millibars, and falling pressure of about 12 hPa per 100 meters of altitude means a mountain road can shave tens of millibars off a barometer reading in a short climb.
1 millibar = 100 pascals (exactly).
Sources: Wikipedia: Bar (unit); Wikipedia: Hectopascal; Wikipedia: Atmospheric pressure
Inch Of Mercury (inHg)
About 3,386.39 pascals. US weather reports and aircraft altimeters quote barometric pressure in inches of mercury.
Barometers in the United States still speak in inches. The inch of mercury is the pressure exerted by a 1-inch (25.4 mm) column of mercury under standard gravity, which is a conventional value of about 3,386.389 pascals. Because mercury's density depends on temperature, older literature that used a 60 degrees Fahrenheit basis gives about 3,376.85 pascals instead.
Its modern home is weather and flying. US weather reports quote barometric pressure in inHg, and North America and Japan give altimeter settings in it. Aircraft at higher altitudes set their altimeters to a standard 29.92 inHg, which is where flight levels come from, and that number equals one standard atmosphere.
Mechanics know it from vacuum and boost gauges. Technicians describe refrigerant-system vacuum in inHg, automotive cooling system fill tools typically hold 22 to 27 inHg of vacuum, and railways once used it for vacuum brakes.
1 inch of mercury = 3,386.38864 pascals (approximately).
Sources: Wikipedia: Inch of mercury; Wikipedia: Standard atmosphere (unit); Wikipedia: Atmospheric pressure
Related conversions
- Inches of mercury to millibars (reverse)
- Millibars to pascals
- Millibars to kilopascals
- Millibars to bars
- Millibars to standard atmospheres
- Millibars to PSI
- Millibars to hectopascals
- Millibars to megapascals
- Millibars to torr
- Millibars to millimeters of mercury
- Pascals to inches of mercury
- Kilopascals to inches of mercury
- Bars to inches of mercury
- Standard atmospheres to inches of mercury
- PSI to inches of mercury
- Hectopascals to inches of mercury
- Megapascals to inches of mercury
- Torr to inches of mercury
- Millimeters of mercury to inches of mercury
See all pressure units.