Torr to mmHg Converter
Common Conversions
| torr | mmHg |
|---|---|
| 1 | 1 |
| 10 | 10 |
| 25 | 25 |
| 50 | 50 |
| 100 | 100 |
| 200 | 200 |
| 400 | 400 |
| 500 | 500 |
| 600 | 600 |
| 700 | 700 |
| 760 | 760 |
| 1000 | 1000 |
Why this conversion matters in chemistry
Vacuum-science to clinical-physics translation crosses this identity. A diffusion-pump manifold sitting at 5 × 10⁻⁶ torr reads as 5 × 10⁻⁶ mmHg on a clinical-style gauge — identical for any practical purpose. The match was locked in by the IUPAC 1964 redefinition that fixed 1 torr at exactly 1/760 of a standard atmosphere, which the mmHg matches at standard mercury-column conditions. The conversion is the everyday type cast at the boundary between physical-chemistry vacuum work (torr) and clinical or physiology equipment (mmHg).
Formula
mmHg = torr × 1 (effectively identical)
Worked Examples
760 torr = 760 mmHg
Standard atmospheric pressure — the anchor.
17.5 torr = 17.5 mmHg
About the vapor pressure of water at 20 °C.
1 torr = 1 mmHg
Base unit equivalence — the conversion in its purest form.
355 torr = 355 mmHg
About atmospheric pressure at the Everest summit.
Frequently Asked Questions
How do I convert torr to mmHg?
Multiply by 1. The two units are identical to within 0.000015% — no real chemistry application notices the gap.
Why are torr and mmHg so close?
The torr was defined to track mmHg. One torr is exactly 1/760 of a standard atmosphere (101,325 Pa); 1 mmHg is the pressure of a 1 mm mercury column under standard gravity. They agree to five decimals.
Which unit is preferred in chemistry papers?
Torr in physical chemistry and vacuum science; mmHg in clinical chemistry and physiology. Both are accepted in general chemistry — pick whichever the audience expects.
Is there any case where torr and mmHg differ meaningfully?
No. The 0.000015% difference sits far below the precision of any routine pressure measurement. Treat them as interchangeable.