Convert Air Pressure and Altitude

A simple calculator for air pressure at a given altitude above sea level. This is an estimate that gives good values under normal weather conditions up to an altitude of 11000 meters. It assumes a temperature of 15°C at sea level. A more accurate calculation, but more complicated, can be made using the barometric formula.

Altitude: meters above sea level
Air pressure: hPa = mbar

Please enter the altitude in meters or the air pressure in hectopascals (= millibars). The other value will be calculated.

The international altitude formula used for the calculation is: air pressure = 1013.25 hPa * [ 1 − 6.5 * altitude / (288150 m) ]5.255

Example: on top of the mountain Zugspitze, at an altitude of 2962 meters, the average air pressure is just over 700 hectopascals.

Physics commonly uses SI units. Here is a calculator to convert units.