Pound per Square Inch (psi)
The pound per square inch is a unit of pressure, used for tire pressure in the US, plumbing systems, and hydraulic equipment. Its symbol is psi.
psi
bar
1 pound per square inch equals
| Bar | 0.0689476 bar |
| Kilopascals | 6.89476 kPa |
About the pound per square inch
Pounds per square inch grew out of imperial engineering practice during the industrial revolution, when steam boiler pressures needed standardized measurement.
In everyday use the pound per square inch appears in tire pressure in the US, plumbing systems, and hydraulic equipment. As a point of reference: a typical US car tire is inflated to about 32 psi.