Pressure altitude at a point in the atmosphere is defined by the level of ambient pressure as per the International Standard Atmosphere.
Pressure altitude is an important value for calculating performance as it more accurately represents the air content at a particular level.
Formula to calculate pressure altitude.
Example:
Suppose the current altimeter reading is 20, calculate the pressure altitude if the field elevation is 500 feet.
Therefore, your pressure altitude is 10,420 feet.
