Free42

Thomas Okken

About this app

Free42 is a re-implementation of the HP-42S calculator and the HP-82240 printer.
It is a complete rewrite, not using any HP code, and it does not require an HP-42S ROM image.
Free42 is an Open Source project. The executables and source code are released under the terms of the GNU General Public License, version 2.
All third-party code used in Free42 is either in the public domain, or licensed under terms compatible with GPLv2, or used with the authors' permission.

Ratings and reviews

Oops! My apologies! I mixed up two different HP emulators. and I was awfully cranky about it. My apologies. Free42 appears to be a pretty good HP calculator emulator, I was just upset because it doesn't look like my favorite, which doesn't work any more. Free42 seems to work just fine. I know there are what, a couple of dozen skins available, too.

This is a great app for all of us RPN nuts out there. I probably have 15 different HP's put out to pasture (in a drawer) that don't get much use as I'm now retired. This has been my everyday, goto calculator since. I plugged in the old Elgin & Knowles astronomic azimuth program which appears to run just fine with current ephemeris data. Send a few bucks in to the developer as this app is worth its weight in gold. I'd rate it higher if possible.

This RPN calculator is delightful to use. It is packed with many advanced features that are intuitive and work well together. I especially like that variables can be given names, custom menu slots are available, and you can write programs to add functionality or speed up a calculation you do often. For those new to the app, I would recommend enabling big stack mode (NSTK) to avoid the limitations of a 4 level stack.

What’s new

Fixed RLN and RRN for negative numbers in BSIGNED mode.

More accurate GAMMA for integer arguments.