Pressure Converter

How it works

Pressure units multiplied because different trades measured different things. This converter routes everything through the pascal, the SI unit, so any pair can be linked: bar, psi, atmosphere, millimetres of mercury and kilopascals all become comparable. The key equivalences: 1 bar = 100,000 Pa = 100 kPa, 1 atm = 101,325 Pa, 1 psi = 6,895 Pa, and 1 bar ≈ 14.5 psi. Note that a bar and an atmosphere are close but not identical — the bar is a round number chosen for convenience, the atmosphere a physical reference. Which unit you meet depends on where you are. European tyre pressures come in bar, American ones in psi, weather reports in hectopascals or millibars (the same thing), diving in bar, and blood pressure in millimetres of mercury — a unit surviving purely because mercury columns were the original instrument.