Air Density Calculator
Air density is the mass of air per cubic meter. It increases with rising atmospheric pressure, falling temperature and falling humidity. The latter is because a H2O molecule weighs less than a N2 or O2 molecule. The saturation vapor pressure can be calculated separately. If this is not specified, the calculation is based on the formula for air over water. Please enter at least air pressure and temperature.
The calculation is:
Gas constant of moist air: Rf = Rt / [ 1 − φ * E/p * ( 1 − Rt/Rd ) ]
With humidity φ between 0 and 1, saturation vapor pressure E in pascals, atmospheric pressure p in pascals, as
the gas constant of dry air Rt = 287.058
and the gas constant of steam Rd = 461.523
The unit of the gas constant is J/(kg*k) = Joule / ( Kilogramm * Kelvin)
Air density = p / ( Rf * T)
T is the temperature in kelvins = temperature in °C + 273.15
The density of the air is mainly determined by the mass of the column of air above a point on earth. Around 10 tons of air mass presses down on one square meter of earth at sea level. We are used to this pressure and have developed under it in the course of evolution, so we do not notice it and it is normal for us. The higher you go, i.e. the further you move up from sea level, the lower the mass of the column of air becomes, so the air pressure and thus the air density also decreases. Temperature and humidity have the following effect: cold objects tend to have a higher density, this is especially true for air (in contrast to liquid water with its density anomaly, hence the word tend). So cold air is denser. High humidity, on the other hand, reduces the density, because water (which is present in the air as a gas) has a lower molecular mass than the nitrogen and oxygen molecules in the air.
Physics commonly uses SI units. Here is a calculator to convert lengths, temperature, pressure, speed and other units.