Ohm-O-Graph [L1 ] is a small tool for calculating resistance and tolerance of a resistor. Just a hack but you may find it useful, e.g. for educational purposes. It makes use of Tcl/Tk which therefore has to be installed on your machine. (The package for Tcl/Tk is named Wish and is installed on most Unix based boxes, including Linux. For Windows, it is available, too.)