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Torr
Pressurescientific

What is a torr?

The vacuum-engineering unit — essentially equivalent to mmHg

Definition

The torr equals 1/760 atm — approximately 133.32 Pa. Essentially equivalent to mmHg but defined slightly differently. Used in vacuum-system engineering and older physics.

Common uses

  • Vacuum-chamber pressure readings
  • Semiconductor manufacturing
  • Older physics literature

🌍 Real-world scale

Low-vacuum: 760 to 25 torr. High-vacuum: 10⁻³ to 10⁻⁹ torr. Semiconductor fabrication: often below 10⁻⁶ torr.

Convert from torr

9 conversions
Torr to Pascal1 Torr = 133.322 PaTorr to Kilopascal1 Torr = 0.1333 kPaTorr to Megapascal1 Torr = 0.0001333 MPaTorr to Bar1 Torr = 0.001333 barTorr to Millibar1 Torr = 1.33322 mbarTorr to Pound per Square Inch1 Torr = 0.01934 psiTorr to Atmosphere1 Torr = 0.001316 atmTorr to Millimeter of Mercury1 Torr = 1 mmHgTorr to Inch of Mercury1 Torr = 0.03937 inHg

Convert to torr

9 conversions
Pascal to Torr1 Pa = 0.007501 TorrKilopascal to Torr1 kPa = 7.50062 TorrMegapascal to Torr1 MPa = 7,500.62 TorrBar to Torr1 bar = 750.062 TorrMillibar to Torr1 mbar = 0.7501 TorrPound per Square Inch to Torr1 psi = 51.7149 TorrAtmosphere to Torr1 atm = 760 TorrMillimeter of Mercury to Torr1 mmHg = 1 TorrInch of Mercury to Torr1 inHg = 25.4 Torr

Tips

  • 1 Torr ≈ 1 mmHg (differ by ~1 ppm — negligible in practice).
  • 1 atm = 760 Torr exactly.
  • Named after Evangelista Torricelli, inventor of the barometer.

Common mistakes

  • Assuming torr and mmHg are truly identical — they differ by ~10⁻⁷; only matters in metrology.
  • Using Torr in everyday context — obscure outside vacuum engineering.
  • Mixing Torr and mTorr without specification.

FAQ about the torr

What is a torr?
The torr equals 1/760 atm — approximately 133.32 Pa. Essentially equivalent to mmHg but defined slightly differently. Used in vacuum-system engineering and older physics.
Where is the torr used?
The torr is commonly used for: Vacuum-chamber pressure readings; Semiconductor manufacturing; Older physics literature.
What is an example of a torr in real life?
Low-vacuum: 760 to 25 torr. High-vacuum: 10⁻³ to 10⁻⁹ torr. Semiconductor fabrication: often below 10⁻⁶ torr.
What category does the torr belong to?
The torr is a unit of pressure, part of the 10-unit pressure category on UnitConv.
How accurate are torr conversions?
All conversion factors follow NIST and BIPM international standards to 8 significant figures — the highest practical accuracy.
Explore all 10 pressure units and their conversions.🎈 Pressure hub →