Free42 is a free re-implementation of the HP-42S scientific programmable RPN calculator, which was made from 1988 until 1995 by Hewlett-Packard. Free42 is a complete rewrite and contains no HP code whatsoever. At this time, the author supports versions that run on PalmOS, Microsoft Windows and Linux.

Installing Free42:

Copy Free42.exe to wherever you want it, e.g. create a directory ‘C:\Program Files\Free42’ and put it there. When Free42 runs, it will create two additional files, Free42State.bin and Free42Print.bin (the calculator’s internal state, and the contents of the print-out window) in the same place where the executable is located. For convenience, create a shortcut to Free42.exe and put it on the desktop or in the Start menu.

Uninstalling Free42:

Remove Free42.exe, Free42State.bin, Free42Print.bin, and any shortcuts you

have created to point to Free42.exe.

Free42 is (C) 2004-2005, by Thomas Okken

Contact the author at

Look for updates, and versions for other operating systems, at

website: [] (