Psychrometric Calculator
Every moist-air property from whichever two you actually measured. ASHRAE Hyland-Wexler saturation pressure, the ice/water split below freezing, real altitude correction — and the state point drawn on a chart.
What did you measure?
Dry bulb plus any one other value. Which one does not matter — all four routes land on exactly the same state.
An ordinary thermometer reading
°C
%
°C
°C
g/kg
Advanced / Custom Input — the measurement
The engine runs in SI either way, so the answer does not change.
Site conditions
This matters more than most calculators admit
m
Filled in from the elevation — override with a real reading
kPa
Advanced / Custom Input — pressure
Compare with a second condition?
Outdoor against indoor, or on-coil against off-coil
°C
%
Advanced / Custom Input — the load
Turns the enthalpy difference into an actual kW. 0 to skip.
m³/s
Comfort check
The comfort zone shifts with what people are wearing
Advanced / Custom Input — the comfort zone
°C
°C
ASHRAE 55 caps humidity ratio rather than relative humidity.
g/kg
Result
Put in a dry bulb and one other value, then press “Work out the properties”.
Estimate only — verify with a licensed engineer and your local code authority before final design or installation.