Enter dry-bulb temperature and one humidity measure — get RH, humidity ratio, dew point, wet-bulb and enthalpy at your pressure.
Open the free calculator →Moist air is fully defined by a temperature, a pressure and one moisture property. From there every other property follows. This tool turns dry-bulb temperature plus RH (or dew point, or wet bulb) into the full psychrometric state — the numbers you need for cooling-tower, dryer, HVAC and dehumidification work.
The saturation pressure p_ws(T) comes from the ASHRAE / Hyland-Wexler correlation. The actual vapour partial pressure is p_w = RH · p_ws.
W = 0.62198 · p_w / (P − p_w) (kg water per kg dry air)
The dew point is the temperature where p_ws(T_dp) = p_w. The specific enthalpy of the mixture is h = 1.006·T + W·(2501 + 1.86·T) kJ/kg dry air.
One state, many uses: the same psychrometric point drives cooling-tower range/approach, air-dryer duty, and condensation checks on ducting and cold surfaces.
| Input | Value |
|---|---|
| Dry-bulb temperature | 30 °C |
| Relative humidity | 60 % |
| Total pressure | 101.325 kPa |
Result: p_ws(30 °C) ≈ 4.246 kPa → p_w ≈ 2.548 kPa; humidity ratio W ≈ 0.0160 kg/kg, dew point ≈ 21.4 °C, enthalpy ≈ 71 kJ/kg. Try it with your own numbers →
W = 0.62198·p_w/(P−p_w) with p_w = RH·p_ws(T).
Dew point depends only on moisture; wet bulb also reflects evaporative cooling and lies between dry-bulb and dew point.
Psychrometrics is one of EnggiBasis' utilities tools — free to try, full suite in Pro (₹99/month).
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