Calcylator
Torr to Pascals

Torr to pascals:
multiply by 133.322

Convert torr to pascals for vacuum systems, lab work and barometers, with a chart, worked examples and the mmHg trap to avoid.

Calcylator Editorial Team

Updated · 5 min read

How many pascals are in a torr?

One torr is 133.3223684 pascals, about 133.3 Pa. It is defined as 1/760 of a standard atmosphere, which is 101,325 Pa.

The unit is named after the physicist Evangelista Torricelli, who invented the mercury barometer. Torr is still used in vacuum technology and many laboratory settings, while the pascal is the SI unit, so converting between them is a regular task.

The torr to pascal formula

Torr to pascals =Pa = Torr × 133.3223684
Pa:
pressure in pascals
Torr:
pressure in torr
133.3223684:
pascals in one torr (101,325 ÷ 760)
To go the other way, multiply Pa by 0.007500616827 to get torr.

  • Pressure

    20 Torr

  • Multiply

    20 × 133.3223684

Pressure in Pa

2,666.4 Pa

The full result is 2666.447368 Pa, about 2.67 kPa.

In reverse, 5,000 Pa is 5,000 × 0.007500616827 = 37.5 torr. As a check, 760 torr should come back to 101,325 Pa, one atmosphere.

  1. Write the pressure in torr.
  2. Multiply by 133.3223684 for pascals.
  3. For pascals to torr, multiply by 0.007500616827.
  4. Check with 100 torr, which is about 13,332 Pa.

Chart: torr to pascals from 1 to 1000

The values below are exact to the digits shown.

Torr to pascals
TorrPascals
1133.3223684
2266.6447368
5666.6118421
101333.223684
253333.059211
506666.118421
10013332.23684
25033330.59211
50066661.18421
1000133322.3684

Seven hundred and sixty torr is 101,325 Pa, one atmosphere, so the 1,000 Torr row is about 1.3 atmospheres.

Where torr to pascals comes up

Vacuum pumps are rated in torr, and a reading of 0.5 Torr is 0.5 × 133.3223684 = 66.66 Pa. A chamber at 0.001 Torr, a typical high-vacuum figure, is only about 0.133 Pa.

Weather and medicine use mmHg, which is practically the same size as the torr. A reading of 120 mmHg is about 120 Torr, or 15,999 Pa, which is close to 16 kPa. This is a unit conversion only, not medical advice.

Gauges on older equipment, such as a mercury manometer, still read in torr, so a lab technician switching to SI data sheets needs the pascal value.

Pumping down a vessel shows the scale. Going from 760 Torr at room pressure to 1 Torr removes more than 99.8 percent of the air, yet 1 Torr is still 133 Pa, so a very good vacuum needs figures far below that.

Common mistakes converting torr to pascals

  • Dividing when you should multiply. A pascal is small, so one torr is over a hundred pascals.
  • Treating the torr as an SI unit. It is not part of SI, so data sheets that follow SI will give pascals instead.
  • Mixing up kPa and Pa. 1 Torr is 0.1333 kPa, so a slip of a thousand is easy.
  • Rounding to 133 on large values. At 760 Torr that gives 101,080 Pa, not 101,325 Pa.

Common questions

How many pascals is 1 torr?

One torr is 133.3223684 pascals, about 133.3 Pa. It comes from dividing a standard atmosphere, 101,325 Pa, by 760. So 760 Torr is exactly one atmosphere, the standard sea-level reference pressure.

How do I convert torr to pascals?

Multiply the torr by 133.3223684. For example, 20 Torr is 20 × 133.3223684 = 2,666.4 Pa. As a rough check, multiply by 133, which gives 2,660 Pa for 20 Torr.

How many torr are in 5000 Pa?

5,000 Pa is about 37.5 torr, found by multiplying 5,000 by 0.007500616827. That is roughly 5 kPa, or about 5 percent of a standard atmosphere, so a modest suction level.

Is a torr the same as mmHg?

Practically yes. One torr and one millimetre of mercury are so close that the difference is irrelevant for most uses, though the torr is defined from the atmosphere. Both are about 133.3 Pa.

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