Convert 120 millimeters of mercury to psi

Explanation

Let's convert 120 millimeters of mercury to pounds per square inch, or mmHg to psi as one could put it.

First, we need to calculate the conversion factor using the units respective values. We find 0.01934.

Then we multiply this conversion factor by the number of millimeters of mercury. In this case 120.

Therefore, 120 millimeters of mercury is approximately equal to 2.3204 pounds per square inch.

Formula

1 mmHg≈0.01934 psi

120 mmHg≈120 × 0.01934 psi

120 mmHg≈2.3204 psi

millimeters of mercurymmHg

dimension	pressure
symbol	mmHg

The conventional millimeter of mercury (mmHg) is a unit of pressure.

Definition of the millimeter of mercury

The conventional millimeter of mercury is defined using a value for the density of mercury of 13595.1 kg/m³ and the standard gravity.

Value in terms of the SI

One millimeter of mercury is 133.3224 pascals. This is an approximation.

NIST Guide to the SI, Appendix B.9

History

The most simple barometer is made of a vertical glass tube from which all air as been removed, with a sealed top and an open base submerged into mercury. The atmospheric pressure then pushes the mercury up the tube until it equalize with the pressure at the base of the column of mercury.

The pressure is then expressed as the height of the column of mercury in millimeters.

The measure is dependent on the temperature and local gravity. To ease conversion between units, the millimeter of mercury has been defined with these parameters respectively fixed to approximately 0 °C and exactly 9.80665 m/s².

Metric mercury units

millimeter of mercury	mmHg	1
centimeter of mercury	cmHg	10
centimeter of mercury at 0 °C	-

pounds per square inchpsi

dimension	pressure
symbol	psi, lbf/in²

The pound per square inch (psi, lbf/in²) or psi is a unit of pressure.

The "pound" in "pound per square inch" is the pound-force, not to be confused with the pound the unit of mass. One pound-force is the force exerted downward by a mass of one avoirdupoids pound on the surface of the Earth.

Definition of the pound per square inch

One psi is equal to the pressure exerted by a force of one pound-force on a surface of one square inch.

Equivalences

One psi is equivalent to:

Other psi units

pound per square inch	psi	1
kilopound per square inch	ksi	1000
megapound per square inch	Mpsi	1 000 000