GO-25 SciRPN

This is a wonderful app. Completely replicates the HP 25 RPN scientific calculator with full fidelity.

Deleted app and reinstalled on my iPhone 6s. Working well now. btw very happy to have the calculator I used in college on my phone!

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...

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'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.

Accurate and beautiful recreation of best calculator HP ever made. Had a 25 and 29c in engin school, loved it. Still have my 43-year-old 29c but battery drains too fast to be usable. This app provides the look, feel and calculation ease of the original. Much better than the junk HP is selling these days. Thanks for taking the time and care to do it right.

Couldn't be better except limiting memory and speed to the original specs for added nostalgic effect.

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.

Everything is great except there seems to be a noticeable delay between key presses and the digit entering that becomes somewhat annoying. i41cx emulator is instantaneous on key presses. However, if you went to university engineering and math courses in the 70's the HP25 is still the HP of choice... The 41 is almost cluttered onscreen because of more keys. The 12c isn't at all for Engineering Types. The 25 is Just Right. Hope you can tighten up the speed on key clicks. Beautiful App.

Installed the latest update and the app no longer runs. The calculator screen appears then disappears. Running iOS 6.1.3. Disappointing.