The NIST/ASME Steam Properties Database is based upon the International Association for the Properties of Water and Steam (IAPWS) 1995 formulation for general and scientific use for the thermodynamic properties of water, this updated version provides water properties from the international standards over a wide range of conditions. Version 3.0 incorporates new IAPWS standards adopted in 2008 for the viscosity and for the melting and sublimation curves and in 2011 for the thermal conductivity. The thermophysical properties included in the STEAM Database are: temperature, Helmholtz energy, thermodynamic derivatives, pressure, Gibbs energy, density, fugacity, thermal conductivity, volume, isothermal compressibility, viscosity, quality, dielectric constant, enthalpy, volume expansivity, dielectric derivatives, internal energy, speed of sound, Debye-Hückel slopes, entropy, Joule-Thomson coefficient, refractive index, Cv, surface tension, Cp, Prandtl number, Kinematic viscosity, Ionization constant (pKw), Virial Coefficients, Exergy. Using a Windows® interface, the STEAM database generates tables and plots of property values at specified conditions corresponding to saturation conditions, a fixed property value (isotherm, isobar, etc.), or individual values of two independent variables. Vapor-liquid, vapor-solid, and liquid-solid saturation calculations with either temperature or pressure specified are available. The user can specify which properties to display and the units in which to enter and display data. Additional features include an interactive on-line help system, the ability to plot calculated points and a wide variety of thermodynamic diagrams, and the capability to copy and paste data to and from other applications.