This RPN calculator always stays on top, whether it's the active application or not. It's very handy when you need to go back and forth between the calculator and another window, but don't want the calculator to get lost.
The RPN behavior in this app is based on classic HP calculators. All the essential functions for everyday calculation are included. All memory registers are saved when you quit the app.
Always on Top RPN Calculator v1.0 MacOSX Retail-CORE