The following tools allow you to calculate the density of moist air by knowing either the temperature, pressure and relative humidity OR temperature, dew point and pressure.
The density of moist air is calculated as the sum of the density of the dry air component of the mixture plus the density of the saturated component of the mixture. In the first calculator, the vapour pressure of water vapour in saturated air at the nominated temperature is calculated and multiplied by the relative humidity to give the actual water vapour pressure. The water vapour pressure is then subtracted from the total pressure to give the pressure of the dry component of the parcel. Densities of the two components are then calculated and summed to give the final answer.