With our pressure calculator, you can estimate the pressure which is exerted by force on a specific area of a surface. In the text below, we have explained what is pressure and what are the most common types of pressure. Read on if you want to learn about pressure definition and pressure formula. You can try our pressure conversion calculator to see how many different units pressure have and how you can calculate them.

What is pressure?

As defined, pressure is a physical quantity which describes the magnitude of a force distributed on the surface of an object. We can distinguish many types of pressure due to the source of its origin. These are, for example:

  • aerostatic pressure - the pressure inside the gas arising from its own weight. Check our air pressure at altitude calculator to find the atmospheric pressure at any altitude and temperature!
  • hydrostatic pressure - analogous to the aerostatic pressure, but in this case, exerted by liquids.
  • acoustic pressure - deviation from the average value of atmospheric pressure, occurring during the propagation of an acoustic wave in it. You can compute the pressure of sound with our dB calculator.

Pressure definition

Our pressure calculator uses the straightforward pressure formula below:

p = F / S


  • p is the pressure,
  • F is the force,
  • A is the area of the surface.

This pressure definition relates to the force which is applied perpendicularly to the surface of the object. You should remember that pressure is scalar and therefore it has no direction (as opposed to the force).

Pressure measurement

Many techniques have already been developed for the measurement of pressure. Instruments which measure and display pressure are called pressure gauges. Usually, measurements are made relative to some specific pressure reference. We distinguish:

  • absolute pressure which is zero-referenced against a perfect vacuum (our pressure calculator computes this pressure),
  • gauge pressure which is zero-referenced against ambient air pressure (absolute pressure minus atmospheric pressure),
  • differential pressure which is zero-referenced against other, specific value of pressure.
Dominik Czernia, PhD candidate