# Air Pressure at Altitude Calculator

This air pressure at altitude calculator is a tool that helps you to calculate the atmospheric pressure at any level and by any temperature.

## What is atmospheric pressure

Air pressure is the pressure exerted by the atmospheric air on the surface of the planet. It changes with altitude and temperature. The higher the elevation, the smaller is the mass of the air overlying the ground. Also, atmospheric pressure increases with the increase of temperature.

The units of pressure are Pascals (symbol: Pa). Try the pressure conversion to recalculate Pascals to other units.

## How to calculate air pressure at altitude

It is necessary to use the barometric formula:

`P = P0 * exp (-g * M * (h-h0) / (R * T))`

Where:

`h`

is the altitude at which we want to calculate the pressure, expressed in meters.`P`

is the air pressure at altitude`h`

.`P0`

is the pressure at the reference level`h0`

. In our pressure calculator it is assumed that the reference level is located as sea level, so`h0 = 0`

.`T`

is the temperature at altitude`h`

, expressed in Kelvins.`g`

is the gravitational acceleration. For Earth,`g = 9.80665 m/s^2`

.`M`

is the molar mass of air. For Earthly air,`M = 0.0289644 kg/mol`

.`R`

is the universal gas constant. Its value is equal to`R = 8.31432 N*m /(mol*K)`

.

The procedure of calculating air pressure at altitude is as follows:

- Choose the altitude at which you want to calculate the atmospheric pressure - for example,
`4000 m`

. - Choose the reference pressure
`P0`

. A typical value for Earth is`1 atm`

, or`101 325`

Pa. - Determine the air temperature - for instance,
`30°C`

. - Type the data into the calculator (remember about correct units).
- You have just obtained the result - in our example, the air pressure at altitude
`4000 m`

is equal to`64557.76 Pa`

.