## About Dew Point Calculator (Formula)

The dew point is the temperature below which the water vapor in a sample of air at constant barometric pressure condenses into liquid water at the same rate at which it evaporates. The dew point is a more accurate measurement of the moisture content in the air compared to relative humidity, which is dependent on temperature and pressure.

The Magnus-Tetens formula is used to calculate the dew point in this calculator. The formula takes into account the temperature, relative humidity, and Magnus coefficients, which determine the saturation vapor pressure over water. The formula is:

**Td = (b × α(T,RH)) / (a – α(T,RH))**

where:

- Td is the dew point in degrees Celsius
- T is the temperature in degrees Celsius
- RH is the relative humidity of the air in percent
- a and b are the Magnus coefficients. As recommended by Alduchov and Eskridge, the value of these are: a = 17.625 and b = 243.04 °C
- α(T,RH) = ln(RH/100) + aT/(b+T)

The formula has an uncertainty of 0.35 °C and is valid for temperatures ranging from -45 °C to 60 °C. The dew point calculator uses this formula to provide accurate results for the dew point, given the temperature and relative humidity of the air.