mmHg to PSI Converter

Vacuum system specifications: vacuum gauges often read in mmHg.

Barometric pressure: standard sea-level pressure of 760 mmHg = 14.696 psi for pressure vessel vacuum ratings.

In the medical device industry, intra-aortic balloon pumps (IABP) for cardiac support, arterial line pressure monitoring in ICU and OR, and intracranial pressure monitoring in neurosurgery all measure pressure in mmHg (or cmH₂O for low-pressure systems like central venous pressure and intracranial pressure), with the mmHg-to-psi conversion required when interfacing with industrial-style pressure monitoring equipment or when documenting pressure values in a paper that uses psi (e.g., medical device validation testing for FDA submission, where pneumatic test pressures may be in psi but the clinical reference is in mmHg).

Vacuum pump performance and ultimate vacuum specifications for laboratory use, freeze drying (lyophilization), and pharmaceutical manufacturing universally use mmHg or torr — a 10⁻³ torr (about 1.93 × 10⁻⁵ psi) ultimate vacuum is a typical 'high vacuum' specification, and the conversion to psi is rarely useful because the numbers become unmanageably small.

Refrigeration and air conditioning evacuation procedures use mmHg or microns (1 micron = 0.001 mmHg = 1.93 × 10⁻⁵ psi) as the target vacuum before charging refrigerant — a 500-micron evacuation target is 0.5 mmHg or 0.00967 psi, and the conversion is required when comparing US-spec micron gauges to European millibar or pascal gauges.

Blood gas analyzers in clinical laboratories measure the partial pressures of oxygen (pO₂) and carbon dioxide (pCO₂) in arterial blood samples, with results reported in mmHg (normal pO₂ 80–100 mmHg, normal pCO₂ 35–45 mmHg) — the conversion to psi (1.55–1.93 psi for normal pO₂) is occasionally required when interfacing with industrial gas analysis equipment or when computing gas flow rates from partial pressure gradients in respiratory therapy devices.

Altitude physiology research uses mmHg for atmospheric pressure (760 mmHg at sea level, 523 mmHg at 10,000 ft, 282 mmHg at 25,000 ft) and for blood gas partial pressures, with the conversion to psi required for aerospace medicine equipment specifications and FAA / EASA pilot physiological training materials.

Vacuum metallurgy and vacuum coating processes for semiconductor and optical thin-film deposition use mmHg and torr for process control (a typical sputtering process operates at 10⁻⁶ to 10⁻⁸ mmHg), with the conversion to psi required only when interfacing with US-spec industrial pressure gauges or when documenting the process parameters in a paper using psi as the unit.