This document describes the development of an application for the calculation of thermodynamic and transport properties of water and steam. The equations implemented in the application are based on the Industrial Standard IAPWS-IF97. This paper serves as a comprehensive collection of current releases of the International Association for the Properties of Water and Steam to formulation IF97 and also covers basics of thermodynamics. Through descriptions of program sequences, important procedures and all required equations it shall be possible to expand upon the created application. The developed program exists as Windows application and as interface for the program Mathcad. Usage of these applications is described and supported by examples. Depiction of the program flow, important procedures and the description of all required equations allow for a continued development of the created application on the basis of the provided source code.