How many inch of mercury in 1 millimeter mercury?
The answer is 0.039370078434096.

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

You can view more details on each measurement unit:

inch of mercury or
millimeter mercury

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

1 pascal is equal to 0.00029529983071445 inch of mercury, or 0.0075006157584566 millimeter mercury.

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

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

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

1 inch of mercury to millimeter mercury = 25.4 millimeter mercury

2 inch of mercury to millimeter mercury = 50.8 millimeter mercury

3 inch of mercury to millimeter mercury = 76.2 millimeter mercury

4 inch of mercury to millimeter mercury = 101.6 millimeter mercury

5 inch of mercury to millimeter mercury = 127 millimeter mercury

6 inch of mercury to millimeter mercury = 152.4 millimeter mercury

7 inch of mercury to millimeter mercury = 177.8 millimeter mercury

8 inch of mercury to millimeter mercury = 203.2 millimeter mercury

9 inch of mercury to millimeter mercury = 228.6 millimeter mercury

10 inch of mercury to millimeter mercury = 254 millimeter mercury

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

inch of mercury to petapascal

inch of mercury to yoctopascal

inch of mercury to inch mercury

inch of mercury to megabar

inch of mercury to newton/square meter

inch of mercury to kilopond/square centimeter

inch of mercury to sthene/square meter

inch of mercury to centimeter mercury

inch of mercury to meganewton/square meter

inch of mercury to pascal

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widely used for barometric pressure in weather reports and aviation in the United States, but is considered somewhat outdated elsewhere.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 millimeter of mercury by definition is 133.322387415 Pa (13.5951 g/cm3 × 9.80665 m/s2 × 1 mm), which is approximated with known accuracies of density of mercury and standard gravity.

The torr is defined as 1/760 of one standard atmosphere, while the atmosphere is defined as 101325 pascals. Therefore, 1 Torr is equal to

101325/760 Pa. The decimal form of this fraction is approximately 133.322368421.

The relationship between the torr and the millimeter of mercury is:

1 Torr = 0.999999857533699 mmHg

1 mmHg = 1.000000142466321 Torr

The difference between one millimeter of mercury and one torr, as well as between one atmosphere (101.325 kPa) and 760 mmHg (101.3250144354 kPa), is less than one part in seven million (or less than 0.000015%). This small difference is negligible for most applications outside metrology.

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