GO-25 SciRPN

This is a wonderful simulation and has become the go-to calculator on both my iPhone and iPad. If I had found it years ago I might have saved myself a fair bit of money and time spent on other calculator apps. If you like to use RPN calculators and keystroke programming, this one deserves your attention. Pros - it’s a calculator first and foremost. There is no CAS or graphing to bloat the app. The stack and program listing windows make keeping track of things very easy. It looks good and the settings are straightforward and useful (thank you for allowing the option to mute the key sounds). Cons - none so far.

I’m very impressed with this program. With the latest update I’m starting to like this app as much as the original calculator. If only the keyboard was the same...

When the on-off switch on my 25C gave out I got a 32SII. For those that had a 25C, the faithfulness of this rendition is amazing. I prefer the 25C emulation to a 42S emulation because it is more Spartan. For those that want more keys to fat-finger (37 instead of 30 is noticeably more crowded) and more programmability (why when for anything serious you have something like Mathematica?) there are at least two emulations of the 42S on the App Store. Nits: The tiny green LEDs, the blue info button, and the fact that the iPhone's status bar are not hidden all distract from the purity of the experience. How about an super-retro mode where all those are gone? A more evocative app icon? Maybe just 0.00 in red LEDs? I didn't find either of the keystroke sounds satisfying so I had to turn sounds off. The 25C had a padded yet definite click that I guess is hard to duplicate. Needs some finger grime and a flaky on/off switch to be like I remember.

It was December 1975 when I bought my very first HP calculator, an HP-25, at the Harvard Coop for US$199, a cost about US$1,000 in 2014 dollars. It was a great product which got me hooked on RPN. When I saw this app, I bought it for the awake of nostalgia and also as a tool. Let me say that it is totally faithful to the original, except that the original had only 49 (not 99) program steps and lost all memory contents when switched off. Strongly recommended from an old timer who has seen the rest and knows the best.

I've used the SciRPN-25 for about 3 months. The calculator emulates the original HP25c accurately, but with more programmable steps. The panel showing the stack and register content make the calculator easier to use compared to the original. No bugs detected yet. The SciRPN-25 replaced my buggy HP-11c emulator. I've written my own programs including: combinations, permutations, amortization, and linear regression. Highly recommended for those who want to replace their aging or non-working Woodstock class HP calculators: 25, 25c, or 29c. In summary, I love this calculator.