Pressure Unit Reference
The Pascal (Pa) is the SI unit of pressure (1 N/m²). Common derived units include kilopascal (kPa = 1,000 Pa) and megapascal (MPa). The standard atmosphere (atm) is defined as 101,325 Pa. PSI (pound-force per square inch) is widely used in the US for tire pressure, hydraulics, and gas. mmHg (millimeters of mercury) is standard in medicine for blood pressure. Bar ≈ 100,000 Pa.