Pressure is defined as force applied perpendicular to the surface of an object per unit area. In engineering, two of the most common units used to quantify this are the Pascal (Pa) and the Pound per square inch (psi).
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 standards.
Pound per square inch (psi): A unit of pressure based on avoirdupois units, 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.
Engineers frequently convert between these units when working with international equipment specifications. For instance, while a pneumatic system might be rated in psi, the sensor data from a global supplier may be provided in Pascals or kilopascals (kPa).
Pascal to Pound per square inch Conversion Reference Table
Pascal (Pa)
Pound per square inch (psi)
0.1
1.4504e-05
0.5
7.2519e-05
1.0
1.4504e-04
2.0
2.9008e-04
5.0
7.2519e-04
10.0
0.0015
20.0
0.0029
50.0
0.0073
100.0
0.0145
500.0
0.0725
1000.0
0.145
Conversion Example: 10 Pa to psi
To convert pressure from Pascals to psi, multiply the value by the conversion factor \(0.00014503774389728312\).
The Pascal is part of the International System of Units (SI), which is based on the meter, kilogram, and second. Because it is derived directly from these base units, it allows for consistent calculations across all scientific disciplines without the need for complex conversion factors.
The Pascal is a very small unit of pressure. In most industrial applications, such as tire pressure or hydraulic systems, values in Pascals result in very large numbers. Using kilopascals (1 kPa = 1,000 Pa) makes the data more readable and manageable for engineering documentation.
"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)