💧 Psychrometric Calculator
Calculate saturation vapor pressure, relative humidity, and dew point for moist air at a given temperature.
What this calculator does
This tool calculates key psychrometric (moist air) properties — saturation vapor pressure, actual vapor pressure, and dew point — from dry-bulb air temperature and relative humidity, useful in HVAC, meteorology, and general climate reference.
The formula
Saturation vapor pressure is estimated with the Magnus-Tetens approximation: Psat = 6.1094 × e(17.625T / (T+243.04)) (in hPa, with T in °C). Actual vapor pressure is Psat × (RH/100). Dew point is then found by inverting the Magnus formula for the temperature at which the actual vapor pressure would equal saturation.
This is a widely used approximation accurate to within about 0.4°C over typical atmospheric temperature ranges, suitable for general reference and planning use.