4.9
2.99K reviews
100K+
Downloads
Content rating
Everyone
Screenshot image
Screenshot image

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
Jun 16, 2022

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
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No data collected
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4.9
2.99K reviews
Robert Rohwer
February 24, 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
February 24, 2021
Free42 is programmable too!
Sylvan dB
September 1, 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
July 23, 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.
1 person found this review helpful
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Thomas Okken
July 22, 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 handling of invalid number keys in BINM and OCTM modes.