Author Topic: Free 15C RPN Scientific Calculator is a Simulation of the HP-15C RPN Calculator  (Read 666 times)

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Free 15C RPN Scientific Calculator is a Simulation of the HP-15C RPN Scientific Calculator ...

You can find an iOS Mobile version Here: Retro 15C RPN Scientific Calculator

When Santa was a child there was this thing called an Abacus - which had been around for millennia by then.
When Santa grew into a teenager there was this thing called a Slide Rule - which went the way of the Buggy Whip, and Corset, in the Mid 70's.
When Santa was a young adult there was this thing called a RPN (Reverse Polish Notation) Scientific Calculator - surprise! Someone still makes these things for 99 Swiss Franks.
About a decade after their introduction: these primitive thinking gadgets evolved into the early desktop computer.
And NOW, about 3 decades after Neanderthal Computer made sparks fly, by banging 2 numbers together, Modern Computer (Or modern mobile device) can reconstruct the joys of RPN Calculators for a whole generation ignorant of their delights.  ::)
Save yourself 99 Swiss Franks and play with this thing instead!!!

Free 15C RPN Scientific Calculator

 This is a simulator for the HP-15C advanced scientific programmable calculator. This simulator aims to include all features of the HP-15C including:

    Complex arithmetic
    Matrix math
    Numerical integration
    Numeric equation solver
    Statistics functions

This simulator has been developed independently and does not rely on any actual HP-15C code or ROM images.


I bought my HP-15C in 1987 as my first RPN calculator, and used it throughout university. I still have my original one, and it continues to operate on the same set of batteries, after 25 years. The form factor (horizontal layout) is the distinctive feature of this family of calculators. There is even a Petition to Bring Back the 15C.

This implementation was inspired by the HP-35 Calculator Simulator at the Museum of HP Calculators.

Known Issues

The following functions are known to be incomplete or nonfunctional:

    Some rounding errors in functions like ->H.MS
    Numeric range checking
    PSE function in a program doesn't actually pause
    Indirect matrix access through I register


This HP15c simulator was developed by Greg Hewgill.

Online version

Click HERE to open the calculator window.

Windows EXE Installer (and uninstaller) (5 MB)
Windows zip file of executables only (no installer) (6 MB)

Mac OS X
Mac OS X disk image (10 MB)
Mac OS X dashboard widget (0.5 MB)

Java Swing desktop app (JAR) (1 MB)


For other platforms, you can download the source code and build it yourself. The Qt version is portable to any platform which supports Qt.


This calculator application should be considered experimental and its results should not be used for anything important. In particular, there are situations where the numeric display is known to be totally wrong.

This web site and software is not associated with HP or is subsidiaries. HP and the HP logo are trademarks of HP.
« Last Edit: August 31, 2019, 12:19:40 PM by Software Santa »


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