Calco ScreenshotCalco is a simple RPM Calculator written on top .NET Framework 3.5 and WPF.

RPN enables much more efficient data entry but requires some training to get familiar with. If you are not familiar with the RPN (Reverse Polish Notation) good starting point is HP Museum or Wikipedia.

Calco RPM Calculator is free to download and use. Prerequisite for Calco is to have Microsoft .NET Framework 3.5 installed. You can get it here. Once .NET Framework is installed, just extract Calco to any folder and run it from there. No special installation required.