Torr to Megapascals (Torr to MPa)

1 torr equals 0.0001333223684 megapascals (rounded).

How to convert torr to megapascals

To convert torr to megapascals, multiply the number of torr by 0.0001333223684. The factor is rounded to 10 significant digits. To go the other way, multiply megapascals by 7,500.616827 (rounded).

megapascals = torr × 0.0001333223684

Example: 10 torr = 0.001333223684 megapascals.

About these units

Torr (Torr)

ScientificCurrent unit

Exactly 1/760 of a standard atmosphere (about 133.322 Pa), named after Evangelista Torricelli. Used for vacuum measurement.

In 1643 Evangelista Torricelli filled a meter-long tube, sealed at one end, with mercury and stood it in a basin of mercury. The column fell to about 76 cm and left a Torricellian vacuum above it, the first recorded creation of a permanent vacuum. In a letter dated 11 June 1644 he described living at the bottom of a sea of air, an idea that also explained why suction pumps could raise water only about 10 meters.

The torr honors him. It was originally meant to equal one millimeter of mercury at 0 degrees Celsius, but the weight of a mercury column varies with gravity, which changes with elevation and latitude. In 1954 the 10th CGPM defined the standard atmosphere as 101,325 Pa, and the torr was then fixed as exactly one 760th of that, about 133.32 Pa.

Today the torr is mostly met in high-vacuum physics and engineering. It differs from the millimeter of mercury by less than one part in seven million, so the two are interchangeable except in the most exacting work.

1 torr = 133.3223684 pascals (approximately).

Sources: Wikipedia: Torr; Wikipedia: Evangelista Torricelli; Wikipedia: Standard atmosphere (unit)

Megapascal (MPa)

Metric (SI)Current unit

One million pascals. Used for material strength and hydraulic pressure.

Engineers reach for the megapascal because the pascal is far too small for solid materials. It is the preferred unit in engineering for stiffness and for tensile or compressive strength, and stiffness figures go on to gigapascals: aluminium is given as 69 GPa, structural steel as 200 GPa, and diamond as 1,220 GPa.

Fluid systems live in the same range. One megapascal is 10 bar, so scuba tanks filled to about 200 bar sit at 20 MPa, and fixed industrial hydraulic machinery commonly working at around 300 bar runs at about 30 MPa. A kilobar, used in experimental petrology, is 100 MPa.

For comparison with units from the pounds-and-inches world, one psi is about 6.895 kPa, so a megapascal is about 145 psi.

1 megapascal = 1,000,000 pascals (exactly).

Sources: Wikipedia: Pascal (unit); Wikipedia: Bar (unit); Wikipedia: Pounds per square inch

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