3K reviews
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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.
Updated on
1 Oct 2022

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No data collected
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3K reviews
Robert Rohwer
24 February 2021
I still have two HP42s, one for my office at work, one for my office at home, both in a drawer. Free42 now resides on my phone and computers. It is a perfect emulation with some significant advantages in stack height and memory. I occasionally miss the HP's programmability, but usually just turn to a spread sheet for highly repetitive calculations or more specialized apps or programs for more challenging work.
7 people found this review helpful
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Thomas Okken
24 February 2021
Free42 is programmable too!
Sylvan dB
1 September 2020
For a calculator app that optimizes keystrokes, this is the one. For the classic HP calculator experience in an app, start here. If you want an RPN calculator, you won't find a consistent, faster, smaller, scientific, featured calculator cheaper. If you want graphing or algebraic or textbook entry, keep looking.
10 people found this review helpful
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Lincoln Ross
23 July 2022
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.
2 people found this review helpful
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Thomas Okken
22 July 2022
I assure you Free42 is still the same app as always. It sounds like you may have accidentally switched skins, though.

What's new

Fixed crash in SHOW for certain complex numbers.

Added A...F function. This allows programs to turn on HEXM mode with the A...F menu activated.

Fixed incorrect Out of Range error returned by BASE functions in certain cases, e.g. BRESET 64 WSIZE 1 ENTER BASE÷