Pressure Converter

Pressure is force per unit area, and the units in everyday use come from different traditions: the pascal is the SI unit, bar and its subunit millibar are common in meteorology and Europe, PSI (pounds per square inch) dominates in the US for tires and plumbing, and 'atmosphere' is defined as exactly 101,325 pascals, close to average air pressure at sea level.

This converter is useful for checking a car or bicycle tire pressure spec given in an unfamiliar unit, reading a scuba diving depth gauge or dive table that mixes bar and PSI, or comparing a weather report's barometric pressure against a different scale.

Meteorologists usually report pressure in hectopascals (hPa) rather than plain pascals, mainly because 1 hPa equals the older millibar unit exactly, so historical weather data lines up numerically — if a figure looks 100 times off from what you expected, check for a hPa/Pa mismatch.