Calculator.NET is an enhanced version of the standard calculator in Microsoft Windows. It uses RPN (Reverse Polish Notation), which is used by many pocket calculators, e.g. from HP. If you have used a HP 11/28/32/42/48, or any other RPN calculator, you will feel right at home. Some of the enhancements included: RPN, extended function set, and customizable user interface. This program is completely free.