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Torr (Torr)

Quantity: pressure · Category: Pressure

The torr is a unit of pressure defined as exactly 1/760 of a standard atmosphere. It is named after Evangelista Torricelli, inventor of the barometer. It was originally intended to equal one millimeter of mercury (mmHg) under standard conditions, and the two are numerically almost identical, so they are often used interchangeably in practice.

Relation to SI

1 Torr = 1/760 atm = 133.322368 Pa

Examples

  • Vacuum systems report pressures in torr, e.g. 10⁻⁶ Torr
  • 760 Torr = 1 atm
  • Manometer readings are commonly given in torr