rpCalc is a simple, graphical open source, RPN (Reverse Polish Notation) calculator.
The software works much like an HP calculator, and all of the commands can be entered using the keyboard or a mouse.
If you know how to use an RPN calculator (like some Hewlett-Packard models), you know how to use rpCalc. It stores previous results in four registers (usually labeled X, Y, Z and T), and the numbers are entered before the operators.
rpCalc started out as a very small program written to try out various Python GUI toolkits, but has evolved into a functional and useful utility.
rpCalc requires Python (version 3.4 or higher), Qt (version 5.4 or higher), and PyQt (version 5.4 or higher).
Key Features
- Uses reverse polish notation, similar to most Hewlett-Packard calculators.
- The number, operator or command text on any key can be typed, or the mouse can be used to hit the key.
- The four RPN registers can optionally be output in the main display.
- A separate window can display the four RPN registers, a history of recent calculations, or the contents of the ten memory registers.
- A separate window converts to and from other number bases (hexadecimal, octal and binary).
- Any values from the extra windows can be copied to the calculator display or to the clipboard.
- Engineering notation display option was added that only shows exponents that are divisible by three.
- Copy Value button that copies the value of the current input mode base to the clipboard for use in other applications.
- Options can be set to control the display of numbers and the initial window configuration.
- Option to remove the LCD display highlight. This is useful for smaller displays.
Website: rpcalc.bellz.org
Support: Documentation
Developer: Douglas W. Bell
License: GNU GPL v2 or any later version

rpCalc is written in Python. Learn Python with our recommended free books and free tutorials.
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Read our verdict in the software roundup.
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