101325

101325 pascals (Pa) is the nominal atmospheric pressure at sea level under the internationally accepted standard atmosphere. It is defined as exactly one atmosphere (atm) and is equal to 101.325 kilopascals (kPa), 1013.25 hectopascals (hPa or mbar). In common usage, it is also approximated as 14.696 pounds per square inch (psi). This value serves as a reference pressure in physics and engineering and is widely used as a baseline for measurements and calculations.

Definition and context are tied to international standardization. The value is used to define 1 atm in many standards and is closely aligned with the average pressure exerted by Earth's atmosphere at sea level under standard conditions. Because it provides convenient unit conversions, 101325 Pa is frequently cited in formulas, calibrations, and engineering specifications.

Applications and relevance. 101325 Pa is used to calibrate instruments such as barometers and pressure transducers, and it serves as a baseline in gas-law calculations (for example, PV=nRT). It also functions as a reference point in many engineering standards when specifying operating conditions or tolerances. In everyday terms, it contrasts with gauge pressure, which measures pressure relative to ambient atmospheric pressure, and with vacuum pressures that are below it.