What is torr?
A torr is a pressure unit equal to approximately 1/760 of an atmosphere. It is used in vacuum technology, low-pressure experimental physics, and blood pressure measurement in older clinical literature.
Real-world uses
Torr is used in vacuum technology, semiconductor manufacturing, and blood pressure measurement (mmHg ≈ torr). Vacuum chambers for electron beam welding operate at about 10⁻⁵ torr, and freeze-drying processes typically operate at 0.1–1 torr.
History
Named after Evangelista Torricelli, who invented the mercury barometer in 1644. The torr was defined to approximate the pressure exerted by 1 mm of mercury. It was formally standardized as 1/760 of a standard atmosphere.
Common mistakes
Assuming torr and mmHg are exactly the same—they are nearly identical but differ by about 0.000015%. For most purposes they are interchangeable, but ultra-precise vacuum work may require distinction.
What is pascal?
The pascal is the SI base unit of pressure, equal to one newton per square metre. It is used in meteorology, fluid dynamics, materials science, and all scientific pressure measurements.
Real-world uses
The pascal is the SI unit of pressure used in engineering stress analysis, materials science, and acoustics (sound pressure levels). Concrete and steel specifications list compressive strength in megapascals (MPa). Atmospheric pressure is about 101,325 Pa.
History
Named after Blaise Pascal, the French mathematician and physicist who conducted pioneering experiments on fluid pressure and vacuum in the 1640s. The pascal was adopted as the SI unit of pressure in 1971 at the 14th General Conference on Weights and Measures.
Common mistakes
Using pascals directly for everyday pressure is impractical since one pascal is a very small pressure (about the weight of a dollar bill spread over a desk). Most practical applications use kPa, hPa, or MPa instead.
When is this conversion used?
Converting between torr and pascal is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region.
Worked examples
1 torr = 133.32236842 pascal
1 pascal = 1 pascal
How to convert torr to pascal
To convert torr to pascal, multiply the value by 133.32236842.
To convert pascal back to torr, multiply by 0.00750062.
Measurement standards
The pascal (Pa) is the SI derived unit of pressure, defined as one newton per square metre. The World Meteorological Organization mandates the hectopascal (hPa) for atmospheric pressure reporting in aviation and weather services.
Did you know?
The pressure at the bottom of the Mariana Trench, nearly 11 km deep, exceeds 1,086 bar — over a thousand times atmospheric pressure. At this depth, water is compressed by about 5%, making it measurably denser than at the surface.
Quick reference: torr to pascal
| torr | pascal |
|---|---|
| 0.1 | 13.33223684 |
| 0.5 | 66.66118421 |
| 1 | 133.32236842 |
| 2 | 266.64473684 |
| 5 | 666.61184211 |
| 10 | 1,333.22368421 |
| 25 | 3,333.05921053 |
| 50 | 6,666.11842105 |
| 100 | 13,332.23684211 |
| 250 | 33,330.59210528 |
| 500 | 66,661.18421055 |
| 1,000 | 133,322.3684211 |
Common values
| torr | pascal | |
|---|---|---|
| Car tyre | 1,650.13570195 torr | 220,000 pascal |
| Standard atmosphere | 760 torr | 101,325 pascal |
| Blood pressure (systolic) | 120.00986923 torr | 16,000 pascal |
| Deep-sea submersible | 825,067.85097429 torr | 110,000,000 pascal |
| Bicycle tyre | 4,650.38243276 torr | 620,000 pascal |