Pressure is defined as force applied perpendicular to the surface of an object per unit area. In engineering, two primary units dominate the landscape: the Pound per square inch (psi) and the Pascal (Pa).
Pound per square inch (psi): A non-SI unit commonly used in the United States and the oil and gas industry. It represents the pressure resulting from a force of one pound-force applied to an area of one square inch.
Pascal (Pa): The SI derived unit of pressure, defined as one newton per square meter (\(1 \text{ Pa} = 1 \text{ N/m}^2\)). It is the standard unit used in scientific research and international engineering projects.
The conversion factor is derived from the gravitational force on a pound mass and the conversion of inches to meters. To convert psi to Pa, we use the relationship: \(1 \text{ psi} \approx 6894.757 \text{ Pa}\).
Pound per square inch to Pascal Conversion Reference Table
Pound per square inch (psi)
Pascal (Pa)
0.1
689.4757
0.5
3447.3785
1.0
6894.757
2.0
13789.514
5.0
34473.785
10.0
68947.57
20.0
137895.14
50.0
344737.85
100.0
689475.7
500.0
3.4474e+06
1000.0
6.8948e+06
Conversion Example: 10 psi to Pascal
To convert a pressure value from psi to Pascal, multiply the given psi value by the conversion factor of 6894.757.
The Pascal is the SI unit of pressure, which ensures consistency across international scientific and engineering disciplines. By using a base-10 system, it simplifies complex calculations in fluid dynamics and thermodynamics compared to the imperial psi system.
The value 6894.757 is a high-precision approximation based on the international standard pound (0.45359237 kg) and the international inch (0.0254 m). For most industrial applications, this level of precision is more than sufficient.
"On fait la science avec des faits, comme on fait une maison avec des pierres ; mais une accumulation de faits n'est pas plus une science qu'un tas de pierres n'est une maison." "Science is built up of facts, as a house is built of stones; but an accumulation of facts is no more a science than a heap of stones is a house." — Henri Poincaré (French Mathematician, Theoretical Physicist & Mining Engineer)