Mmhg to Psi Converter
Common Conversions
| mmHg | psi |
|---|---|
| 5.171 | 0.1 |
| 25.857 | 0.5 |
| 51.715 | 1 |
| 103.43 | 2 |
| 258.575 | 5 |
| 517.149 | 10 |
| 760 | 14.696 |
| 1034.299 | 20 |
| 1551.448 | 30 |
| 2585.747 | 50 |
| 5171.493 | 100 |
Why this conversion matters in chemistry
Medical-gas regulator testing is a typical place to need it. A 760 mmHg ventilator-drive pressure on the patient-side gauge is 14.70 psi on the cylinder-side regulator — the bridge value a biomed technician references when checking regulator droop against NFPA 99 medical-gas specifications. The constant of 1/51.7149 psi per mmHg is the standard-atmosphere identity (1 atm = 760 mmHg = 14.6959 psi). In practice you reach for it when SI mercury-column readings need to land in the US psi form pneumatic equipment uses.
Formula
psi = mmHg ÷ 51.7149 (equivalently, psi = mmHg × 0.0193368)
Worked Examples
760 mmHg = 14.696 psi
Standard atmospheric pressure expressed in both unit systems.
51.715 mmHg = 1 psi
Exactly one psi in mmHg — the conversion anchor in reverse.
25.857 mmHg = 0.5 psi
Half a psi — about a low-vacuum gauge reading.
1551.45 mmHg = 30 psi
30 psi — about a typical compressed-gas regulator output.
Frequently Asked Questions
How do I convert mmHg to psi?
Divide by 51.7149. So 760 mmHg becomes 14.70 psi. The factor is exact through the standard-atmosphere identity 1 atm = 760 mmHg = 14.6959 psi.
Why do US labs see both mmHg and psi?
Traditional lab instruments — mercury barometers, blood-pressure cuffs, McLeod gauges, Schlenk-line manometers — are graduated in mmHg (or torr, which is essentially identical). US-built gas regulators, cylinder gauges, and pneumatic equipment use psi. Bridging the two is routine in any synthesis or analytical lab.
How many mmHg is 1 psi?
About 51.715 mmHg per psi. The factor is exact through the international agreement on the standard atmosphere.