ThermoSolver is an educational thermodynamics software program designed to be both easy to use and useful in that it permits the user to make nontrivial chemical engineering thermodynamic calculations. The software program accompanies the textbook Engineering and Chemical Thermodynamics by Milo Koretsky, and is available for free download from the Web. ThermoSolver has a built-in database of chemical properties, and contains a number of sub-programs which perform calculations such as finding saturation pressures and fugacities, solving of equations of state, solving vapor-liquid equilibrium problems, and determining chemical reaction equilibria. The software has been integrated into the problems and examples in the textbook by Koretsky; it compares favorably with similar educational software, and has been used in several chemical engineering classes taught at Oregon State University and elsewhere.