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atmosphere [standard] atmosphere [technical] |

How many inch of mercury in 1 atmosphere?
The answer is 29.921255347142.

We assume you are converting between **inch of mercury [0 °C]** and **atmosphere [standard]**.

You can view more details on each measurement unit:

inch of mercury or
atmosphere

The SI derived unit for **pressure** is the pascal.

1 pascal is equal to 0.00029529983071445 inch of mercury, or 9.8692326671601E-6 atmosphere.

Note that rounding errors may occur, so always check the results.

Use this page to learn how to convert between inches of mercury and atmospheres.

Type in your own numbers in the form to convert the units!

1 inch of mercury to atmosphere = 0.03342 atmosphere

10 inch of mercury to atmosphere = 0.33421 atmosphere

20 inch of mercury to atmosphere = 0.66842 atmosphere

30 inch of mercury to atmosphere = 1.00263 atmosphere

40 inch of mercury to atmosphere = 1.33684 atmosphere

50 inch of mercury to atmosphere = 1.67105 atmosphere

100 inch of mercury to atmosphere = 3.34211 atmosphere

200 inch of mercury to atmosphere = 6.68421 atmosphere

You can do the reverse unit conversion from atmosphere to inch of mercury, or enter any two units below:

inch of mercury to petabar

inch of mercury to centihg

inch of mercury to picopascal

inch of mercury to nanobar

inch of mercury to centimeter water

inch of mercury to hectobar

inch of mercury to millibar

inch of mercury to foot mercury

inch of mercury to femtopascal

inch of mercury to foot of head

Inches of mercury or inHg is a non-SI unit for pressure. It is still widely used for barometric pressure in weather reports and aviation in the United States, but is considered somewhat outdated elsewhere.

It is defined as the pressure exerted by a column of mercury of 1 inch in height at 32 °F (0 °C) at the standard acceleration of gravity.

1 inHg = 3,386.389 pascals at 0 °C.

Aircraft operating at higher altitudes (above 18,000 feet) set their barometric altimeters to a standard pressure of 29.92 inHg or 1,013.2 hPa (1 hPa = 1 mbar) regardless of the actual sea level pressure, with inches of mercury used in the U.S. and Canada. The resulting altimeter readings are known as flight levels.

Piston engine aircraft with constant-speed propellers also use inHg to measure manifold pressure, which is indicative of engine power produced.

The standard atmosphere (symbol: atm) is a unit of pressure defined as 101325 Pa (1.01325 bar). It is sometimes used as a reference pressure or standard pressure. It is approximately equal to Earth's atmospheric pressure at sea level.

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