i41CX

This is a great program! The interface is so well designed and uses all of the available screen space so that the numbers are readable for this old timer. In the HP tradition, this app exceeds expectations in both quality and performance.

Well done! $/feature/functionality it’s like buying a hand held super computer. Holy cow! Not to mention throw-back value for boomer generation :)

I have been using HP calculators since I bought a HP45 in about 1973 With HP mostly out of the Scientific RPN calculator area this app fills the need! Makes me miss my HP41CV I had (that died after many years of heavy use). Super customer service as well.

UPDATE - The display issue from v7.6.1 is fixed - via 7.6.2. The calc is now back to the great tool that it has been for quite a while and I look forward to continuing to use it for another few years. Thanks. PRIOR - The most recent update may have made for compatibility with the latest iOS (I haven't tried it yet on my iPhone and likely won't based on this experience) but it no longer works on my iPad that has an older iOS. The background graphics no longer scale up to the screen size so the touch points for the calc do not agree with the visual indications for the buttons. Avoid this version. Wait until it is fixed if you have an iPad with an older iOS.

I wore out my HP-41 calculator but it was the thing that brought me back to programming after a nauseating experience with FORTRAN 77 in 1981. I wrote nearly 200 programs on that calculator. It got me through engineering school, taking the PE, working on the Hubble, B2, and 7x7s. I’m glad to have it back, even just as a calculator. I’m curious: Can I still write a subroutine to cause the calculator to automatically shut down when I turn it on using flag 11?

Latest speed enhancement is phenomenal! Thank you. Now if we can have it always “ON” when it comes up, then it would be perfect! Is there a setting that would have turn on automatically when it starts?

Love it love the way the case looks 35 years using one now have it on me

For all the reasons HP RPN scientific calculators are used for engineering, this calculator is simply the best. All the features of the best HP calculators, with improvements. Outstanding.

I LOVE the way it reproduces the look as well as the action of the calculator. It just wouldn’t be the same without emulating the case, the ports everything. That is for this final but critical extra touch.

I used an HP-41c for years in engineering. This now is far more convenient and true to the original. Developer is also very responsive.