A simple computer tool based on MS Excel for estimating several physical, transport, and thermodynamic properties is presented. The properties included in the software are critical properties (Tc,Pc,Vc, andZc), normal boiling temperature, acentric factor, density, heat capacity, thermal conductivity, viscosity, surface tension, speed of sound, melting temperature, and heat of melting. Different types of models previously proposed by the authors are used and the limitations of each model are clearly stated. These models include group contributions, semiempirical correlations, equations of state, and the geometric similitude equation of state concept. The calculations provided by the software do not aim to replace experimental data but help in obtaining a good estimate before going to the lab to experimentally measure a given property. The software is available free of charge and can be modified for particular applications.