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 megapascal?
A megapascal is a pressure unit equal to one million pascals. It is used for measuring high pressures in industrial hydraulics, structural materials testing, and deep-sea and geological applications.
Real-world uses
Megapascals are used for concrete compressive strength (typical structural concrete is 20–40 MPa), steel tensile strength (mild steel ≈ 250 MPa yield), and hydraulic system pressures. Geologists use MPa for rock stress and tectonic pressure at depth.
History
The megapascal became a standard engineering unit with the global adoption of SI. It provides a convenient scale for material strength and high-pressure applications, replacing older units like kgf/cm² and ksi (kilopounds per square inch) in most countries.
Common mistakes
Confusing MPa with kPa—they differ by a factor of 1,000. Specifying concrete strength as 30 kPa instead of 30 MPa would describe an impossibly weak material. Also, 1 MPa = 1 N/mm², a useful equivalence often forgotten.
When is this conversion used?
Converting between torr and megapascal 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 = 0.00013332 megapascal
1 megapascal = 1,000,000 pascal
How to convert torr to megapascal
To convert torr to megapascal, multiply the value by 0.00013332.
To convert megapascal back to torr, multiply by 7,500.61682704.
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 megapascal
| torr | megapascal |
|---|---|
| 0.1 | 0.00001333 |
| 0.5 | 0.00006666 |
| 1 | 0.00013332 |
| 2 | 0.00026664 |
| 5 | 0.00066661 |
| 10 | 0.00133322 |
| 25 | 0.00333306 |
| 50 | 0.00666612 |
| 100 | 0.01333224 |
| 250 | 0.03333059 |
| 500 | 0.06666118 |
| 1,000 | 0.13332237 |
Common values
| torr | megapascal | |
|---|---|---|
| Car tyre | 1,650.13570195 torr | 0.22 megapascal |
| Standard atmosphere | 760 torr | 0.101325 megapascal |
| Blood pressure (systolic) | 120.00986923 torr | 0.016 megapascal |
| Deep-sea submersible | 825,067.85097429 torr | 110 megapascal |
| Bicycle tyre | 4,650.38243276 torr | 0.62 megapascal |