pressure · Medical/scientific/technical · Modern

millimetre of mercury (conventional)

exact

Definition

1 mmHg (conventional) = 133.3224 Pa

One millimetre of mercury (conventional) is exactly 133.3224 pascals.

Mercury-column pressure units arose from manometry; modern standards distinguish a conventional mmHg conversion from the separately defined torr.

Modern use is context-dependent and varies by region or measurement system.

Source tier — · confidence high

pressure · International · Modern

SI derived unit of pressure and stress; 1 Pa = 1 N/m² = 1 kg·m⁻¹·s⁻².

pressure · International · Modern / historical

1 bar = exactly 100,000 Pa.

psi

pressure · United States · Modern

1 psi = exactly 6894.757293168361 Pa using international lb/in and standard gravity.

pressure · International · Modern

1 atm = 101325 Pa exactly

pressure · Scientific/technical · Modern/historical

1 Torr = (1/760) atm = 101325/760 Pa

pressure

1 hPa = 100 Pa; conventional inHg converts using NIST factors.