Torr
The torr is defined as exactly 1/760 of a standard atmosphere (101 325/760 Pa). It is almost, but not exactly, equal to one millimetre of mercury.
Symbol: Torr
Quantity: pressure, stress and differential pressure (force per unit area)
SI relation: 1 Torr = 133.3223684211 Pa (exact)
Derivation: 1 Torr = 101325/760 Pa = 133.3223684 Pa (1/760 of a standard atmosphere)
Exact: yes, by definition
History
Named after Evangelista Torricelli, who built the first mercury barometer in 1644.
Typical uses
- Vacuum technology and vacuum gauges
- Thin-film deposition and sputtering (mTorr range)
- Mass spectrometry and electron microscopy
Convert torr to other units
| Conversion | 1 Torr equals | Reverse |
|---|---|---|
| torr to pascal | 133.3223684 Pa | pascal to torr |
| torr to kilopascal | 0.1333223684 kPa | kilopascal to torr |
| torr to psi | 0.0193367747 psi | psi to torr |
| torr to bar | 0.001333223684 bar | bar to torr |
| torr to millimeter of mercury | 0.9999998575 mmHg | millimeter of mercury to torr |
| torr to inch of water | 0.5352400812 inH₂O | inch of water to torr |
| torr to atmosphere | 0.001315789474 atm | atmosphere to torr |
| torr to megapascal | 0.0001333223684 MPa | megapascal to torr |
| torr to millibar | 1.333223684 mbar | millibar to torr |
| torr to millimeter of water | 13.59509806 mmH₂O | millimeter of water to torr |
| torr to centimeter of water | 1.359509806 cmH₂O | centimeter of water to torr |
| torr to inch of mercury | 0.03937007313 inHg | inch of mercury to torr |
| torr to decibar | 0.01333223684 dbar | decibar to torr |
| torr to inch of water (60 °F) | 0.5357754719 inH₂O (60 °F) | inch of water (60 °F) to torr |
| torr to barye | 1333.223684 Ba | barye to torr |
Open the Pressure Converter to convert any value between all units.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "torr (Torr)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Torr. Retrieved October 17, 2026, from https://scientificconverters.com/units/torr/
IEEE
Scientific Converters, "Torr," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/units/torr/