gsmc is a GTK application that allow to do all the calculation usually done on a Smith Chart. It permits to make calculation for network composed by resistor, capacitor, inductance, and transmission line (also as stub). Network topology is limited to series, parallel and as trasmissive for trasmission line. No series connection are allowed in parallel branch, neither parallel connection in series branch. Trasmission line can be placed as quadrupole or as a parallel or series stub, either opened or shorted at the other end. Calculation procedure starts with setting the initial impedance to be matched, next network elements are added and tuned to obtain the desidered impedance value. The network so obtained can be saved in spice format for other analysis; current work can be saved for succesive retrieve. The initial (start) impedance is thought as "the load" so when adding a trasmission line placed as a quadrupole rotation is clockwise, going "toward generator"; generator is placed after the last network element, as can be seen from spice output.