Pascal

This article is about the unit of pressure; for other uses see Pascal (disambiguation)

The pascal (symbol Pa) is the SI unit of pressure. It is equivalent to one newton per square metre. The unit is named after Blaise Pascal, a French mathematician, physicist and philosopher.

Since 1 Pa is a small pressure, the unit hectopascal (symbol hPa) is more widely used, especially in meteorology. The unit kilopascal (symbol kPa) is also in common use.

1 hectopascal = 100 pascal = 1 millibar

1 kilopascal = 1000 pascal = 10 hectopascal

Standard atmospheric pressure is 101,325 Pa = 101.325 kPa = 1013.25 hPa = 1013.25 mbar.

The same unit is used to measure stress, Young's modulus and tensile strength.

Table of contents

1 Examples of various values (approximately)
2 Comparison to other units of pressure
3 External links

Examples of various values (approximately)

(See SI prefix for guide to units.)

0.5 Pa Atmospheric pressure on Pluto (1988 figure; very roughly)
9.81 Pa The pressure caused by a depth of 1 mm of water¹
1 kPa Atmospheric pressure on Mars
10 kPa The pressure caused by a depth of 1 m of water, or
the drop in air pressure when going from sea level to 1000 m elevation¹
101.3 kPa Atmospheric pressure at sea level¹
10 MPa Pressure washer forces out water at this pressure
100 MPa Pressure at bottom of Mariana Trench, about 10 km under ocean¹
10 GPa Diamond forms
100 GPa Theoretical tensile strength of carbon nanotubes (CNTs)
¹at the Earth's surface

Comparison to other units of pressure

1 bar 100,000 Pa
1 millibar 100 Pa
1 atmosphere 101,325 Pa
1 mmHg (or torr) 133 Pa
1 inch Hg 3,386 Pa