New -21 and -25 apps for iPhone


Maciej Bartosiak has ported my simulation code for the -21 and -25 calculators to iOS, so they may be used on the iPhone, iPod Touch, and iPad. The apps are RPN-21 and RPN-25. I hope no one objects to my posting this announcement; I thought some of the regulars here might be interested in these apps.


Really nice looking calculator! Well, at least the 21 version. I'm not paying $2.99 for a iPhone version, sorry. ;-)



You can credit Maciej for the visual appearance, as that's entirely his doing. I'll take the blame for any bugs in the simulation.


I got them both for my iPad. Finally an HP-25 emulator!!! I am a happy camper!!!




Glad you like it! If we're successful with it, more models will likely follow.



An HP 27 and/or HP 29c would be nice. ;-)


From your lips to the developers' ears!!

I hope Eric is reading this!



Edited: 6 Mar 2011, 9:25 a.m.


I don't mind paying a reasonable fees for these emulators.


Thanks! these are great apps :-)


Nice looking for sure. BTW, please note all shifted functions are located below of the primary operations :-)

For edition 1.1 I'd suggest an improved exponent format - e.g. sin^-1 looks a bit primitive spelled this way IMHO. And a capital Pi is used ... :-/


Great app !
A couple of comments:

1/This is obviously not a HP-25C: killing the app resets memory; on Iphone 4 this is not much of a problem, you can use multitasking to keep the memory state, but still - is there any plan to upgrade it to a HP-25C in future ?

2/I think there is a bug: I never owned a HP-25 but I think it is supposed to display the next instruction to be excuted if "SST" is held down (and then, to excute the instruction). Here, nothing of this kind. Is this a bug or an intended behaviour ?

Would be awsome to have the 34C (and of course, the 65 and 67, if ever their card reader behaviour is reversed-engineered...).




You're right about SST on the 25. I'll talk to Maciej about that and continuous memory.



Hi Eric,
Thanks, the new version is on the Appstore and corrects the 'SST' bug ! It does not implement continuous memory, though.
Could you maybe tell us what is scheduled for Nonpareil for Iphone ? Especially:
-If the calculators that are already in Nonpareil, especially the 34C and 33C, could be soon on the Appstore ? would be great !
-If the calculators that are not yet in Nonpareil, but that you have been mentionning in 2008 as almost-ready (especially, the 67 and the 29C) could come soon as well ?
-and if other calcls (especially the 65, would be great) could come and when ?

Would love of these beauties on my Iphone :)

Thanks and cheers,



Great work! Unfortunately, my original iPod Touch is stuck at OS 3.1.3 so I'll have to wait until I upgrade to a newer "i" device.




I have downloaded the 25 on my iPad. The calculator looks nice. A help file would have helped. However it is nice to play with an HP calculator in 1970s style.

Possibly Related Threads…
Thread Author Replies Views Last Post
  HP-25 Wayne Selway 1 1,250 11-22-2013, 12:58 PM
Last Post: Michael de Estrada
  HP Prime: the drama of the Apps button, shutdown, formatting, nothing solves Davi Ribeiro de Oliveira 0 1,123 11-17-2013, 07:23 AM
Last Post: Davi Ribeiro de Oliveira
  HP-70 Simulation for iPhone Willy R. Kunz 2 1,504 11-17-2013, 07:12 AM
Last Post: Namir
  HP Prime: the drama of the Apps button, shutdown, formatting, nothing solves Davi Ribeiro de Oliveira 1 1,364 11-16-2013, 11:26 PM
Last Post: Michael de Estrada
  More Prime problems - lost Apps key again Michael de Estrada 10 3,028 11-16-2013, 12:46 PM
Last Post: Michael de Estrada
  HP Prime: do not send programs and shuts down by pressing Apps Davi Ribeiro de Oliveira 1 1,374 11-12-2013, 11:05 AM
Last Post: Joseph Ec
  HP Prime - Grouping Apps bluesun08 1 1,219 11-07-2013, 09:23 AM
Last Post: Tim Wessman
  Shutdown with the Apps key and more than 10 variables in a program. Davi Ribeiro de Oliveira 10 3,861 11-05-2013, 01:26 PM
Last Post: Han
  What does the Send menu key in the Apps window do? John Colvin 3 1,627 10-23-2013, 10:56 AM
Last Post: Tim Wessman
  Rearanging the "Fixed" sort order of Prime's Apps icons Joe Horn 3 1,723 10-02-2013, 10:24 AM
Last Post: Han

Forum Jump: