pound-force/square inch Unit Converter

Definition of pound-force/square inch unit

Pound-force per square inch (psi) is a unit of pressure equal to one pound-force exerted uniformly over an area of one square inch. One psi equals approximately 6,894.76 pascals, or 0.0689476 bar.

History of pound-force/square inch unit

The pound-force per square inch developed from British and American customary measurement systems, which combined the avoirdupois pound-force with the square inch. It became established during the industrial era as engineers and manufacturers needed practical pressure measurements for steam machinery, hydraulics, and compressed gases. The abbreviation psi gained widespread acceptance in the nineteenth and twentieth centuries, particularly in English-speaking countries. Although the pascal is the International System of Units standard, psi remains deeply rooted in engineering, transportation, and commercial specifications, reflecting the continuing influence of customary units.

Applications of pound-force/square inch unit

Today, psi is used to specify tire inflation, pipeline and hydraulic-system pressures, scuba-tank and diving equipment ratings, and compressor outputs. Automotive service commonly recommends tire pressures in psi, while manufacturers label gauges, pumps, regulators, and pressure vessels accordingly. In North America, psi also appears in plumbing, refrigeration, aerospace, and industrial safety documentation, often alongside pascals or bar.

Complete list of pound-force/square inch unit conversion