ChemSheet is a novel software tool to perform thermochemical calculations directly from Excel^®-worksheets.  Both multi-phase systems and processes with streams can be calculated, while the ChemSheet software allows both reaction kinetics and heat transfer to be taken into account with the RATEMIX^®-algorithm.  An extensive range of non-ideal solution models can be used, in particular those interesting for material scientists, inorganic chemists as well as for pyro- and hydrometallurgists.