In vacuum technology and industrial process engineering, precise pressure measurement is critical. The Torr is a non-SI unit of pressure defined as exactly \(1/760\) of a standard atmosphere. It is named after Evangelista Torricelli and is widely used in high-vacuum applications, such as thin-film deposition and mass spectrometry.
The Bar is a metric unit of pressure, defined as \(10^5\) Pascals. While not an SI unit, it is accepted for use with the SI system and is the standard unit for industrial process control, pneumatic systems, and meteorological reporting.
Torr: Primarily used in laboratory settings and vacuum systems where low-pressure precision is required.
Bar: The industry standard for hydraulic systems, gas pipelines, and general industrial pressure monitoring.
To convert between these units, we utilize the relationship where \(1 \text{ Torr} \approx 0.00133322 \text{ bar}\).
Torr to Bar Conversion Reference Table
Torr (Torr)
Bar (bar)
0.1
1.3332e-04
0.5
6.6661e-04
1.0
0.0013
2.0
0.0027
5.0
0.0067
10.0
0.0133
20.0
0.0267
50.0
0.0667
100.0
0.1333
500.0
0.6666
1000.0
1.3332
Conversion Example: 10 Torr to Bar
To convert a pressure value from Torr to bar, multiply the Torr value by the conversion factor of \(0.0013332239999999998\).
Step 1: Identify the input value: \(P_{\text{Torr}} = 10\).
Torr remains the industry standard in vacuum science because it relates directly to the height of a mercury column in a barometer, which was historically the most accurate way to measure vacuum levels. It provides a convenient scale for low-pressure ranges where Pascal values would involve cumbersome scientific notation.
Yes, the conversion is based on the definition of the standard atmosphere. Since 1 atmosphere is defined as 101,325 Pascals and also as 760 Torr, the conversion factor is exactly 101,325 divided by 760, resulting in the precise value of 0.0013332239999999998 bar per Torr.
"On fait la science avec des faits, comme on fait une maison avec des pierres ; mais une accumulation de faits n'est pas plus une science qu'un tas de pierres n'est une maison." "Science is built up of facts, as a house is built of stones; but an accumulation of facts is no more a science than a heap of stones is a house." — Henri Poincaré (French Mathematician, Theoretical Physicist & Mining Engineer)