Convert Torr to Millimeters of Mercury
1 torr equals 0.9999998575 millimeters of mercury (mmHg).
1 Torr = 0.9999998575 mmHg
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk torr to millimeter of mercury converter to paste a column from Excel.
How to Convert Torr to Millimeter of Mercury
- 1 Torr = 0.9999998575 mmHg
- 1 mmHg = 1.000000142 Torr
- Example: convert 15 Torr to mmHg: 15 Torr = 15 × 0.9999998575 mmHg = 14.99999786 mmHg
Reference conditions. mmHg: Conventional mercury column: ρ = 13 595.1 kg/m³ and gₙ = 9.80665 m/s² (≈ mercury at 0 °C / 32 °F).
Formula
mmHg = Torr × 0.9999998575337
or mmHg = Torr ÷ 1.000000142466
Derivation from SI units:
- 1 Torr = 101325/760 Pa = 133.3223684 Pa (1/760 of a standard atmosphere)
- 1 mmHg = 13 595.1 kg/m³ × 9.80665 m/s² × 0.001 m = 133.322387415 Pa
- 1 Torr = 133.3223684211 Pa ÷ 133.322387415 Pa per mmHg = 0.9999998575337 mmHg
Both units are defined exactly, so the factor is exact. Torr definition: torr; Millimeter of Mercury definition: millimeter of mercury.
Worked examples
- 1 Torr equals 0.9999998575 mmHg.
1 Torr × 0.9999998575 = 0.9999998575 mmHg - A rough-vacuum reading of 100 Torr is 99.99998575 mmHg.
100 Torr × 0.9999998575 = 99.99998575 mmHg
Torr to Millimeter of Mercury conversion table
| Torr | Millimeters of Mercury (mmHg) |
|---|---|
| 0.000001 Torr | 9.999998575 × 10⁻⁷ mmHg |
| 0.00001 Torr | 0.000009999998575 mmHg |
| 0.0001 Torr | 0.00009999998575 mmHg |
| 0.001 Torr | 0.0009999998575 mmHg |
| 0.01 Torr | 0.009999998575 mmHg |
| 0.1 Torr | 0.09999998575 mmHg |
| 0.5 Torr | 0.4999999288 mmHg |
| 1 Torr | 0.9999998575 mmHg |
| 5 Torr | 4.999999288 mmHg |
| 10 Torr | 9.999998575 mmHg |
| 50 Torr | 49.99999288 mmHg |
| 100 Torr | 99.99998575 mmHg |
| 250 Torr | 249.9999644 mmHg |
| 500 Torr | 499.9999288 mmHg |
| 750 Torr | 749.9998932 mmHg |
| 760 Torr | 759.9998917 mmHg |
| 1000 Torr | 999.9998575 mmHg |
Where it's used
Vacuum and physiology references switch freely between torr and mmHg. The values agree to seven significant figures.
Torr to other pressure units
| Conversion | 1 Torr equals |
|---|---|
| torr to pascal | 133.3223684 Pa |
| torr to kilopascal | 0.1333223684 kPa |
| torr to megapascal | 0.0001333223684 MPa |
| torr to psi | 0.0193367747 psi |
| torr to bar | 0.001333223684 bar |
| torr to millibar | 1.333223684 mbar |
| torr to decibar | 0.01333223684 dbar |
| torr to millimeter of mercury | 0.9999998575 mmHg |
| torr to millimeter of water | 13.59509806 mmH₂O |
| torr to centimeter of water | 1.359509806 cmH₂O |
| torr to inch of water | 0.5352400812 inH₂O |
| torr to inch of water (60 °F) | 0.5357754719 inH₂O (60 °F) |
| torr to inch of mercury | 0.03937007313 inHg |
| torr to atmosphere | 0.001315789474 atm |
| torr to barye | 1333.223684 Ba |
Frequently asked questions
Why do torr and mmHg differ at all?
The torr is defined as 1/760 atm. The conventional mmHg is defined from a mercury density of 13 595.1 kg/m³ and standard gravity, which gives a value about 0.14 ppm larger.
How many millimeters of mercury are in 1 torr?
1 Torr = 0.9999998575 mmHg.
How do I convert torr to millimeters of mercury?
Multiply the value in Torr by 0.9999998575, or divide it by 1.000000142. For example, 15 Torr × 0.9999998575 = 14.99999786 mmHg.
Is the Torr to mmHg conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "torr (Torr)".
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "millimeter of mercury, conventional (mmHg)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Torr to Millimeters of Mercury. Retrieved October 17, 2026, from https://scientificconverters.com/pressure/torr-to-millimeter-of-mercury/
IEEE
Scientific Converters, "Convert Torr to Millimeters of Mercury," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/pressure/torr-to-millimeter-of-mercury/