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Definitions
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Pounds per square inch
The pounds per square inch [psi] is a unit of pressure and stress according to the Imperial and US customary systems of units. The unit is derived from the pound-force lb-f, a unit of force and the inch squared, which is a unit of area. The psi unit describes how many pounds (force) are applied on a unit area of square inch. The definition of psi depends on the definitions of the pound-force and the inch units.
Pound-force [lb-f] is defined as the force of gravity on the earth's surface upon a mass equal to one avoirdupois pound. Its equivalence to the respective metric unit, the Newton [N] is: 1 lb-f = 4.4482216152605 N. The above definition depends on the earth's gravity g, which varies from place to place, but is typically standardized as g ≈ 9.80665 m/s2 ≈ 32.174049 ft/s2.
Inch [in] is a unit of length for the Imperial and US customary system of units. It was historically conceived as the length of 3 barley-corns. Today, it is defined through the meter [m] SI unit as: 1 in = 0.0254 m (= 2.54 cm = 25.4 mm).
With the above definitions of lb-f and the inch, relative to their metric equivalents, the conversion rule from psi to KPa becomes:
The relationship between psi and other units of pressure and stress are shown in the following table:
| Unit | Symbol | [psi] |
|---|---|---|
| Kilopascal | KPa | 0.1450377 |
| Bar | bar | 14.50377 |
| Standard atmosphere | atm | 14.69595 |
| Torr | Torr | 0.01933678 |
Kilopascal
Kilopascal [KPa] is a unit of pressure and stress according to the SI system of units. It is a multiple of Pascal [Pa] (1 KPa = 1000 Pa), which is a derived unit, based on the Newton [N], a unit of force and the meter squared, which is a unit of area. The Pa unit describes how many Newtons (force) are applied on a unit area of square meters.
The relationship between KPa and other units of pressure and stress are shown in the following table:
| Unit | Symbol | [kPa] |
|---|---|---|
| Pascal | Pa | 0.001 |
| Megapascal | MPa | 1000 |
| Gigapascal | GPa | 1 000 000 |
| Pounds per sq. inch | psi | 6.89476 |
| Bar | bar | 100 |
| Standard atmosphere | atm | 101.325 |
| Torr | Torr | 0.1333224 |
How to convert pounds per sq. inch to kilopascal (psi to KPa)
- Multiply pressure/stress in psi with 6.89476
- The result is the pressure/stress in KPa
For example 10psi is 10x6.89476 ≈ 68.95 KPa
How to convert kilopascal to pounds per sq. inch (KPa to psi)
- Divide pressure/stress in KPa by 6.89476
- The result is the pressure/stress in psi
For example 100 KPa is 100/6.89476 ≈ 14.50 lb
Conversion table from KPa to psi
In the following table some typical pressures in KPa are converted to psi:
| [KPa] | [psi] |
|---|---|
| 1 | 0.145 |
| 5 | 0.7252 |
| 10 | 1.45 |
| 20 | 2.901 |
| 30 | 4.351 |
| 40 | 5.802 |
| 50 | 7.252 |
| 70 | 10.15 |
| 90 | 13.05 |
| 100 | 14.5 |
| 150 | 21.76 |
| 200 | 29.01 |
| 300 | 43.51 |
| 400 | 58.02 |
| 500 | 72.52 |
| 600 | 87.02 |
| 700 | 101.5 |
| 800 | 116 |
| 900 | 130.5 |
| 1000 | 145 |
| 2000 | 290.1 |
| 3000 | 435.1 |
Conversion table from psi to KPa
In the following table some typical pressures in psi are converted to KPa:
| [psi] | [KPa] |
|---|---|
| 0.25 | 1.724 |
| 0.5 | 3.447 |
| 0.75 | 5.171 |
| 1 | 6.895 |
| 2 | 13.79 |
| 3 | 20.68 |
| 4 | 27.58 |
| 5 | 34.47 |
| 6 | 41.37 |
| 7 | 48.26 |
| 8 | 55.16 |
| 9 | 62.05 |
| 10 | 68.95 |
| 12 | 82.74 |
| 15 | 103.4 |
| 20 | 137.9 |
| 25 | 172.4 |
| 30 | 206.8 |
| 35 | 241.3 |
| 40 | 275.8 |
| 45 | 310.3 |
| 50 | 344.7 |
| 60 | 413.7 |
| 70 | 482.6 |
| 80 | 551.6 |
| 90 | 620.5 |
| 100 | 689.5 |
| 150 | 1034 |
| 200 | 1379 |