Psychrometric Calculator

Enter dry-bulb temperature plus relative humidity, dew point, or wet-bulb to calculate all psychrometric air properties instantly.

Inputs

Results

Enter values and click Calculate.

Note: Calculations assume standard atmospheric pressure (101.325 kPa / 14.696 psia) and use ASHRAE Fundamentals equations. Accuracy is within ±0.1 °C / ±0.2 °F across the comfort range (−10 °C to 60 °C).

Summary

Enter dry-bulb temperature plus relative humidity, dew point, or wet-bulb to calculate all psychrometric air properties instantly.

How it works

  1. Enter the dry-bulb temperature (the standard thermometer reading).
  2. Choose a second input: relative humidity (%), dew point, or wet-bulb temperature.
  3. Select your preferred unit system: SI (Celsius) or Imperial (Fahrenheit).
  4. The calculator derives saturation vapor pressure using the Antoine/Magnus equation.
  5. From vapor pressure and temperature it computes humidity ratio, dew point, wet-bulb, and enthalpy.
  6. Results update instantly as you type.

Use cases

  • Verify HVAC system performance against design psychrometric conditions.
  • Size cooling coils and dehumidifiers for commercial and residential projects.
  • Convert field measurements (dry-bulb + wet-bulb from a sling psychrometer) to full air state.
  • Calculate enthalpy difference across an AHU cooling or heating coil.
  • Determine dew point to avoid condensation on cold surfaces.
  • Support commissioning reports and energy-audit documentation.
  • Check data-center air supply conditions against ASHRAE thermal guidelines.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu