# Pascal (unit)

The **pascal** (symbol: **Pa**) is the unit of pressure in the International System of Units (SI), and is also used to quantify internal pressure, stress, Young's modulus, and ultimate tensile strength. The unit, named after Blaise Pascal, is defined as one newton per square metre[1] and is equivalent to 10 barye (Ba) in the CGS system. The unit of measurement called standard atmosphere (atm) is defined as 101,325 Pa.[2]

pascal | |
---|---|

General information | |

Unit system | SI |

Unit of | Pressure or stress |

Symbol | Pa |

Named after | Blaise Pascal |

Conversions | |

1 Pa in ... | ... is equal to ... |

SI base units: | kg⋅m^{−1}⋅s^{−2} |

US customary units: | 1.45038×10^{−4} psi |

atmosphere: | 9.86923×10^{−6} atm |

bar: | 10^{−5} bar |

barye (CGS unit) | 10 Ba |

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.

Meteorological observations typically report atmospheric pressure in hectopascals per the recommendation of the World Meteorological Organization, thus a standard atmosphere (atm) or typical sea-level air pressure is about 1013 hPa. Reports in the United States typically use inches of mercury[3] or millibars (hectopascals).[4][5] In Canada these reports are given in kilopascals.[6]