›› Convert millimeter water [4 °C] to

millimeter water
inch mercury

›› More information from the unit converter

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!

›› Quick conversion chart of millimeter water to inch mercury

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

›› Want other units?

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

Enter two units to convert


›› Common pressure conversions

millimeter water to centimeter of water
millimeter water to kilonewton/square meter
millimeter water to foot of water
millimeter water to zettabar
millimeter water to inch water column
millimeter water to centitorr
millimeter water to decibar
millimeter water to pieze
millimeter water to zettapascal
millimeter water to kilobar

›› Definition: Inch mercury

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widely used for barometric pressure in weather reports and aviation in the United States, but is considered somewhat outdated elsewhere.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

›› Metric conversions and more

ConvertUnits.com provides an online conversion calculator for all types of measurement units. You can find metric conversion tables for SI units, as well as English units, currency, and other data. Type in unit symbols, abbreviations, or full names for units of length, area, mass, pressure, and other types. Examples include mm, inch, 100 kg, US fluid ounce, 6'3", 10 stone 4, cubic cm, metres squared, grams, moles, feet per second, and many more!