3.13K reviews
Content rating
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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
May 15, 2024

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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Ratings and reviews

2.84K reviews
A Google user
August 18, 2019
Incredible RPN calculator! If you like HP calculators, this is flat out amazing! It has the same layout as the original HP-42s. It even runs the same programs -- but much faster than the original! There's a "haptic feedback" option which feels something like the actual HP key clicks. There are other layouts if you like a horizontal layout. The settings screen is accessible if you touch the calculator display.
11 people found this review helpful
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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.
13 people found this review helpful
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Thomas Okken
February 24, 2021
Free42 is programmable too!
A Google user
March 31, 2024
I have the original HP 41 c and 42S. Then HP got lost. F re42S is a must for my Android phones and tablets. I use it daily and it is very Highly recomended.
3 people found this review helpful
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What's new

PSE could halt program execution if it was used right after TONE or BEEP. Fixed.