MEASUREMENT & METHODS

Pounds per square inch (psi): pressure unit guide

Understand pounds per square inch (psi) for pressure. Check base-unit equivalents, examples, comparison tables and source conventions.

What is being measured?

Pressure is force per area. Unit scaling cannot change a gauge-pressure reading into an absolute-pressure reading without the reference pressure.

Atmospheres are standard atmospheres. Mercury-column factors use the conventional 0 °C definition; torr is 1/760 of a standard atmosphere.

Meaning of psi

Pounds per square inch uses the symbol psi in this library and measures pressure. Under the stated reference convention, 1 psi = approximately 6894.75729317 Pa. This equivalence changes how a known value is written. It does not increase measurement accuracy or establish whether a measurement is appropriate to a real application.

Conversion method

Multiply the value by the source factor (6894.757293168), then divide by the target factor (1). The factor ratio expresses the same pressure measurement in the other unit.

Worked example

For a known value of 10 psi, the reference conversion gives 68947.5729317 Pa. Converting that result back gives approximately 10 psi. This reverse check helps catch a reversed factor, but matching round-trip arithmetic alone does not independently verify a source definition.

Common reference values

Input (psi)Reference equivalent (Pa)
16894.75729317
534473.7864658
1068947.5729317
25172368.932329
50344737.864658
100689475.729317

Compare one psi with other units

Target unitEquivalent of 1 psiDefinition guide
Pascals (Pa)6894.75729317Read definition
Kilopascals (kPa)6.89475729317Read definition
Bars (bar)0.0689475729317Read definition
atmospheres (atm)0.0680459639099Read definition
megapascals (MPa)0.00689475729317Read definition
millibar (mbar)68.9475729317Read definition
Conventional millimetres of mercury (mmHg (0 °C))51.7149252039Read definition
Conventional inches of mercury (inHg (0 °C))2.03602067732Read definition

Precision and common mistakes

  • Keep the source and target quantity consistent. A matching symbol is not enough to establish a compatible definition.
  • Record the original measurement precision. Showing twelve significant digits in a table does not make a rounded input more precise.
  • Check symbol capitalization, prefixes and any regional convention in the source. Use the displayed unit definition rather than a similarly named unit.
  • Factors involving repeating fractions or π use finite numerical precision. Round the final answer to the precision justified by your input.

Use a working converter

Source and verification scope

Examples and tables are computed from the versioned unit definitions used by the linked converters. The source access dates appear below. Computandum is independent of the cited organizations; a citation does not mean that a publisher endorses this page or an actual project.

Sources

Read the calculation and sourcing methodology →