How many millimeter water in 1 inch mercury?
The answer is 345.31557667501.

We assume you are converting between **millimeter water [4 °C]** and .

You can view more details on each measurement unit:

millimeter water or
inch mercury

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

1 pascal is equal to 0.10197162129779 millimeter water, or 0.00029529980164712 inch mercury.

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

Use this page to learn how to convert between millimeters water and inches mercury.

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

1 millimeter water to inch mercury = 0.0029 inch mercury

10 millimeter water to inch mercury = 0.02896 inch mercury

50 millimeter water to inch mercury = 0.1448 inch mercury

100 millimeter water to inch mercury = 0.28959 inch mercury

200 millimeter water to inch mercury = 0.57918 inch mercury

500 millimeter water to inch mercury = 1.44795 inch mercury

1000 millimeter water to inch mercury = 2.8959 inch mercury

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

millimeter water to attopascal

millimeter water to centipascal

millimeter water to yottapascal

millimeter water to torr

millimeter water to zettapascal

millimeter water to pascal

millimeter water to dekabar

millimeter water to yoctobar

millimeter water to micropascal

millimeter water to hectopascal

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widely used for barometric pressure in weather reports and aviation in the United States, but is considered somewhat outdated elsewhere.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.

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