Hectopascal

Pascal
A pressure gauge reading in psi (red scale) and kPa (black scale)
Unit information
Unit system	SI derived unit
Unit of	Pressure or stress
Symbol	Pa
Named after	Blaise Pascal
Unit conversions
1 Pa in ...	... is equal to ...
SI base units:	kg⋅m−1⋅s−2
US customary units	1.450377×10−4 psi

The pascal (symbol: Pa) is the SI derived unit of pressure used to quantify internal pressure, stress, Young's modulus and ultimate tensile strength. It is defined as one newton per square meter. It is named after the French polymath Blaise Pascal.

Common multiple units of the pascal are the hectopascal (1 hPa = 100 Pa) which is equal to one millibar, and the kilopascal (1 kPa = 1000 Pa) which is equal to one centibar.

The unit of measurement called standard atmosphere (atm) is defined as 101,325 Pa and approximates to the average pressure at sea-level at the latitude 45° N.Meteorological reports typically state atmospheric pressure in hectopascals.

The unit is named after Blaise Pascal, noted for his contributions to hydrodynamics and hydrostatics, and experiments with a barometer. The name pascal was adopted for the SI unit newton per square metre (N/m²) by the 14th General Conference on Weights and Measures in 1971.

The pascal can be expressed using SI derived units, or alternatively solely SI base units, as:

where N is the newton, m is the metre, kg is the kilogram, and s is the second.