Steam table calculator: water and steam properties by temperature and pressure
Choose what you know: temperature, pressure, or both. The calculator works out whether the water is saturated, compressed liquid or superheated steam, and returns specific volume, enthalpy and entropy.
v = v_f + x(v_g − v_f), h = h_f + x·h_fg, s = s_f + x(s_g − s_f)
How to use it
For saturated water, one temperature or one pressure is enough, because the two are tied. You get the properties of saturated liquid (f) and saturated vapour (g). If you also know the quality x, the mass fraction that is vapour, you get the properties of the mixture.
If you know both temperature and pressure, the calculator compares them with the saturation line: below the boiling point it is compressed liquid, above it superheated steam.
Example
Steam at 1 MPa (1000 kPa) and 300 °C is superheated, because water boils at 179.89 °C at that pressure. The calculator gives v = 0.25798 m³/kg, h = 3051.7 kJ/kg and s = 7.1247 kJ/kg·K, as in the steam tables.
About the calculation
Values come from IAPWS-IF97, the industrial standard for water and steam properties, and are checked against the verification values the standard publishes. The same code computes the steam tables on this site, and it is open source on GitHub and npm as engineering-tables.
The calculator does not cover the region near the critical point, roughly above 350 °C and 16.5 MPa, where the standard uses a separate equation. There it says so instead of returning a number.