Use this chemistry calculator to reproduce a named relationship with explicit quantities and units for study, laboratory planning, or an independent numerical check.

Dewpoint temperature (°C)

Required number input.

Compute water vapor pressure from dewpoint temperature using the Magnus formula. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Vapor pressure (hPa)

The resulting vapor pressure returned as a number.

• Humidity and wet-bulb relationships depend on pressure, temperature scales, phase conventions, ventilation, and the selected saturation-vapor-pressure correlation. Local measurements and full psychrometric methods are needed for precision work.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check units and significant figures, compare the result with limiting cases, and use measured or source-specific constants where available. Laboratory, safety, and regulatory decisions require validated methods and appropriate uncertainty analysis.

• Dewpoint From Vapor Pressure

  Invert the Magnus formula to compute dewpoint temperature from water vapor pressure.

• Barometric Pressure

  Estimate atmospheric pressure at altitude from temperature using the barometric formula.

• Clausius–Clapeyron Vapor Pressure

  Estimate vapor pressure at a second absolute temperature from a reference pressure and molar enthalpy of vaporization using the integrated Clausius–Clapeyron equation. Assumes vapor behaves ideally and enthalpy stays constant over the temperature interval.