Pascal (Pa)

The SI unit of pressure equal to one newton per square meter

The Pascal (Pa) is a unit of pressure with a history connected to the study of fluids, gases, and atmospheric phenomena. Evangelista Torricelli's invention of the barometer in 1643 was a landmark in pressure measurement, and subsequent work by Blaise Pascal established the mathematical foundations. The pascal — the SI unit — was named in Pascal's honor when the SI system was formalized. The Pascal reflects either the SI tradition or the practical conventions of specific industries that standardized their measurements independently.

Accurate pressure measurement is critical in engineering, science, commerce, and everyday life. Using the correct unit and applying conversions precisely prevents errors that can be costly or dangerous in professional applications.

Conversion Table

UnitSymbol1 Pa =
KilopascalkPa0.001 kPa
Barbar0.00001 bar
Atmosphereatm0.00000986923 atm
Pound per Square Inchpsi0.000145038 psi
Millimeters of MercurymmHg0.00750064 mmHg
MegapascalMPa0.000001 MPa
GigapascalGPa1.000000e-9 GPa
Kilopound per Square Inchksi1.450377e-7 ksi
Torrtorr0.00750064 torr
Inch of MercuryinHg0.0002953 inHg
Kilogram-force per Square Centimeterkgf/cm²0.0000101972 kgf/cm²

Conversions Involving Pascal

Common Uses of the Pascal

  • Automotive — inflating tires to manufacturer-specified pressures
  • Weather reporting — tracking barometric pressure for forecasting
  • Hydraulic systems — designing and operating fluid power equipment
  • Scuba diving — calculating safe dive depths based on partial pressures
  • Medical — measuring blood pressure and calibrating medical equipment

Did You Know?

The deepest point in the ocean — the Challenger Deep in the Mariana Trench — has a water pressure of approximately 110 MPa, or about 1,086 times standard atmospheric pressure. The Pascal is one of several units used to express pressures across this extraordinary range.