Bar to Pounds per Square Inch Converter

Pressure is force spread over an area, and its SI unit is the pascal (Pa), defined as one newton per square metre. A pascal is tiny, so everyday pressures use larger units: the bar (100,000 Pa), the kilopascal, and the standard atmosphere. One atmosphere — roughly the air pressure at sea level — is 101,325 Pa, which is 1.01325 bar, 14.696 psi or 760 mmHg. Different fields keep their own favourites: weather forecasts use hectopascals or millibars (the two are identical, both 100 Pa); tyre and industrial pressure use psi, bar or kilogram-force per square centimetre; blood pressure and vacuum work use millimetres of mercury (mmHg) and the torr, which are all but identical. Column units like mmHg, inches of mercury and inches of water come from the height of a liquid, so they fold in the liquid’s density and gravity. Every unit here is stored as its exact number of pascals, so any conversion is just the input turned into pascals and then into the target unit. Note that gauge pressure (psig, barg) measures above the surrounding air, while absolute pressure includes it — this tool converts the numeric value and leaves that choice to you.