## About Relative Humidity Calculator (Formula)

Relative humidity is the measure of the amount of water vapor in the air as compared to the maximum amount of water vapor that can be present at the given temperature. It is expressed as a percentage and is an important parameter in weather forecasting, indoor comfort, and various industrial processes.

The formula to calculate relative humidity depends on the measurement of two factors: dew point and air temperature. The dew point is the temperature to which the air must be cooled to become saturated with water vapor, while air temperature is the temperature of the air. The formula to calculate relative humidity is:

**RH = (e / es) x 100%**

Where RH is the relative humidity expressed as a percentage, e is the vapor pressure of the water in the air, and es is the saturation vapor pressure at the same temperature.

In some cases, it may be more convenient to use the dew point temperature and air temperature to calculate relative humidity. In that case, the following formula can be used:

**RH = 100 x [exp((17.27 x TD) / (TD + 237.3)) / exp((17.27 x T) / (T + 237.3))]**

Where RH is the relative humidity expressed as a percentage, T is the air temperature in Celsius, and TD is the dew point temperature in Celsius.