Free42

- May 29, 2017

Everyone

( 1,807)

Description

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.

Reviews

4.7

1,807 total

5 1,533

4 185

3 36

2 17

1 36

An absolutely outstanding replica of the best STEM calc ever! You won't find an original HP App for this model, since HP knows they simply can't compete with the impressive work done by Thomas. Please, download, enjoy, and donate to keep this project's updates going on! :0)

James Grant

I have been an HP-4x fan since I was an engineering student in the early 80's. Free42 is an excellent and true emulator that I use on a daily basis. Sadly, my real one sits at home most of the time, now. Great job you guys!

Mike B

Since my HP15C died, I have relied on Free42 on all my computing devices. A worthy replacement.

Phillip Musumeci

Excellent reimplementation of what was/is a stand out calculator. I personally liked the 32S but alas its LCD failed, and this is a perfect replacement.

John Clarke

Its a great app that is always with you when you want to do some quick calcs. I pass it on to as many people as I can. Still have my old HP42 somewhere, but this is better.

Bill Hodges

I am a professional Surveyor and this is my go to calculator

User reviews

June 6, 2017

James Grant May 29, 2017

Mike B June 7, 2017

Since my HP15C died, I have relied on Free42 on all my computing devices. A worthy replacement.

Phillip Musumeci June 16, 2017

Excellent reimplementation of what was/is a stand out calculator. I personally liked the 32S but alas its LCD failed, and this is a perfect replacement.

John Clarke May 29, 2017

Its a great app that is always with you when you want to do some quick calcs. I pass it on to as many people as I can. Still have my old HP42 somewhere, but this is better.

Bill Hodges June 14, 2017

I am a professional Surveyor and this is my go to calculator

Craig Maloney May 29, 2017

This is an excellent implementation of a classic calculator. Responsive and clean. Thank you!

July 2, 2017

Best RPN programmable. I have this on all my devices.

Mike Bordner June 6, 2017

Great app! Good job

Jacques Winter June 1, 2017

Super

Richard Saunders May 29, 2017

Can't live without it

May 30, 2017

Excellent!

Simon Nelson May 11, 2017

Can you program it for calculations?

Thomas Okken May 11, 2017

Yes. Go to http://thomasokken.com/free42/ (scroll down to the Documentation section) to learn more.

Søren Nilsson May 16, 2017

Must have RPN Calculator

Rubén Iglesias May 31, 2017

Love it! Excellent work. Thanks

Richard Merifield May 6, 2017

Excellent emulator

Marco Trevisani April 26, 2017

The best calculator I found so far.

April 26, 2017

Love this calculator!

Nicholas Coffey May 1, 2017

transcendental functions don't work neither do exponentials

Thomas Okken May 11, 2017

I'm not aware of any problems with those functions. Where do you think they give incorrect results?

Duncan Murray April 27, 2017

a great piece of open source android software

Philip Bogardus April 2, 2017

Really like the app. Love RPN and struggle to use phone calculator. Being an engineer geek RPN is a must to do all the cool stuff engineers do.

Gordon Dyer April 1, 2017

A great app I have used for many years. I have been hoping to see the full precision results for just a long, thank you Thomas!

April 2, 2017

Great app! So used to RPN that I can't use the calculator that came with the phone

Antony Langmann April 1, 2017

Wonderful app. Really useful

Mike Jones April 1, 2017

Just what I needed

James Skaggs March 12, 2017

My favorite calculator app! RPN is the way to go, especially with involved calculations! I still regret trading away my 42s, but this is even better, since it is so handy. I use "Notification Toggle" so I can pull down a notification and get the calculator anytime.

Michael E March 25, 2017

This works great. I am so used to my hp 35S that this makes quick phone calcs on my phone simple. The app icon looks horrible though. With that, graphics are horrible that you would think the app sucks at first glance. But it actually does what I need it to.

Rui S May 1, 2017

Thanks for this app.its well done,reliable, free and very nice to use. Its almost seem it was easy to be done. But sure it wasnt.there must be hundreds of hours of work behind it. So thank again for your dedication.

Fagrie Salie March 13, 2017

Superb app ... its like the real calculator in your had ... 42s .. really handy calc ... it has the power with out the bulk ... really nice app ... enjoy .... could add n help function which could with key strokes etc ...

Tony Gozdz March 14, 2017

Like the real thing I still keep on my desk--love them both!

Marco Zunino March 25, 2017

Great, but remember to download the optional skins.

March 12, 2017

Great calculator app for those of us whose upbringing taught us how to use one properly.

A Google User March 12, 2017

thank you on heptic feedback

Coenraad Vrey March 12, 2017

A great RPN calculator!

James Wilson March 12, 2017

Awesome!! Nice job. Love it!

Turb0 Flat4 February 3, 2017

I won my 42S in a tech quiz and treasured it for more than a decade until the LCD went black. I was crushed. And then I found this wonderful app. Even if it can't replicate the joyous feel of those wonderful hard keys, it's surely the next best thing. I've downloaded and printed out the free manual too, since I seem to have misplaced the original. I'm a happy camper!

January 26, 2017

Absolutely wonderful--exactly what I needed. Now I have easy access to my favorite RPN calculator wherever I go. I love the audio click keypress feedback, and being able to switch between portrait and landscape calculator keyboard layouts by rotating my tablet. Thank you so much for developing this app.

Isix Boraxlapo February 27, 2017

Absolutely fantastic, as good as my real HP 42 from years past. As far as I am concerned, this particular calculator was one of the best all around simple to use models HP ever made and it's great to now have it with me all the time on my phone.

January 23, 2017

Better than the original HP 42S. The ability to import programs much easier than re-entering code.Familiar RPN preserved. Fantastic. Reloaded app onto new Huawei P9.

January 23, 2017

Fantastic implementation of the 42S. Indispensable app for every RPN enthusiast! 5/5 for a very professional product. Great work Thomas.

What's New

2.0.4

Implemented special-case code for pure real and pure imaginary numbers in all the complex logarithmic, trigonometric, and hyperbolic functions.

2.0.3

Fixed a few edge cases in complex functions.

On cold start, now clearing flags 21 (printer enable) and 55 (printer existence), to match the behavior of the real HP-42S.

Removed "raw text" print option; it has been obsolete since the introduction of UTF-8 printing in 1.5.11, since Unicode can represent the HP-42S character set directly.

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