The article gives a short survey on the numerical calculation of the thermodynamic state values and their partial derivations for water and steam. The basis for this is the ＇＇IAPS Formulation 1984 for the Thermodynamic Properties of Ordinary Water Substance for Scientific and General Use＇＇, which at present is the best account of the thermodynamic properties of water and steam. This formulation is based on the Hemholtz-function. dependent on density and temperature. Besides this form of presentation, a calculation procedure is here discussed, which enables the determination of the thermodynamic properties, also as function of temperature and pressure, as well as of pressure and density.