# ››Convert inch mercury [0 °C] to pound/square inch

 in Hg psi

The above form works if you are measuring differential pressure, such as the difference in psi between two points. It also gives the correct answer for absolute pressure, assuming you are measuring psia, which is the pressure relative to absolute zero vacuum.

If you are measuring relative to vacuum and want to resolve the pressure relative to the atmosphere, then you should use the form below.

in Hg (relative to vacuum)
psi (relative to atmosphere)

How many in Hg in 1 psi? The answer is 2.0360206576.
We assume you are converting between inch mercury [0 °C] and pound/square inch.
You can view more details on each measurement unit:
in Hg or psi
The SI derived unit for pressure is the pascal.
1 pascal is equal to 0.000295299830714 in Hg, or 0.000145037738007 psi.
Note that rounding errors may occur, so always check the results.
Use this page to learn how to convert between inches mercury and pounds/square inch.
Type in your own numbers in the form to convert the units!

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You can do the reverse unit conversion from psi to in Hg, or enter any two units below:

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widely used for barometric pressure in weather reports and aviation in the United States, but is considered somewhat outdated elsewhere.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

# ››Definition: Pound/square inch

The pound per square inch or, more accurately, pound-force per square inch (symbol: psi or lbf/in² or lbf/in²) is a unit of pressure or of stress based on avoirdupois units. It is the pressure resulting from a force of one pound-force applied to an area of one square inch.

# ››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!