The thermodynamic modeling software MELTS is a powerful tool for investigating crystallization and melting in natural magmatic systems. Rhyolite‐MELTS is a recalibration of MELTS that better captures the evolution of silicic magmas in the upper crust. The current interface of rhyolite‐MELTS, while flexible, can be somewhat cumbersome for the novice. We present a new interface that uses web services consumed by a VBA backend in Microsoft Excel^©. The interface is contained within a macro‐enabled workbook, where the user can insert the model input information and initiate computations that are executed on a central server at OFM Research. Results of simple calculations are shown immediately within the interface itself. It is also possible to combine a sequence of calculations into an evolutionary path; the user can input starting and ending temperatures and pressures, temperature and pressure steps, and the prevailing oxidation conditions. The program shows partial updates at every step of the computations; at the conclusion of the calculations, a series of data sheets and diagrams are created in a separate workbook, which can be saved independently of the interface. Additionally, the user can specify a grid of temperatures and pressures and calculate a phase diagram showing the conditions at which different phases are present. The interface can be used to apply the rhyolite‐MELTS geobarometer. We demonstrate applications of the interface using an example early‐erupted Bishop Tuff composition. The interface is simple to use and flexible, but it requires an internet connection. The interface is distributed for free from http://melts.ofm‐research.org.