Enter temperature, select formula, and click Calculate.

The saturated vapor pressure (e_s) is the pressure exerted by water vapor when the air is in thermodynamic equilibrium with liquid water or ice at a given temperature. At saturation, the rate of evaporation equals the rate of condensation. The Magnus formula is a widely used empirical equation: e_s = 6.112 × exp((17.67 × T) / (T + 243.5)), where T is in °C and e_s is in hPa. The Clausius-Clapeyron equation provides a theoretical framework derived from thermodynamics, relating vapor pressure to temperature through the latent heat of vaporization. This relationship is fundamental in meteorology, climatology, HVAC design, and environmental science. Understanding saturated vapor pressure is essential for calculating relative humidity, dew point, and atmospheric stability. The calculator provides results in multiple units: hPa, mmHg, atm, and kPa, making it versatile for various scientific and engineering applications.

1. Enter the Temperature in degrees Celsius (°C). Valid range: -50°C to 200°C.
2. Select the Formula – Magnus (empirical) or Clausius-Clapeyron (theoretical).
3. Click Calculate Vapor Pressure to compute the saturation pressure.
4. The result shows pressure in hPa, mmHg (Torr), atm, and kPa.
5. Below 0°C, the calculation refers to equilibrium with ice.
6. Click Reset to restore default example values.