GO-25 SciRPN simulates the venerable HP-25C Programmable Scientific Calculator. The HP-25C was released in 1976 and sold for a MSRP of $195. Virtually indistinguishable from the real item in operation, GO-25 is a powerful yet simple retro calculator.

•Requires iOS 8.0 or higher
•Copy / Paste
•Shake to clear X
•Programmable with 99 program steps, conditionals, full-speed or single step operation
•Built-in library of sample programs
•iTunes File Sharing
•Swipe-up gesture that displays the stack and memory registers, and the program listing views
•For iPad two finger drag operations for displayed views
•Addition, subtraction, multiplication, division
•Trigonometric functions : sin, cos, tan, sin⁻¹, cos⁻¹, tan⁻¹, degrees, radians or grads
•Rectangular/polar coordinate conversion
•Hours, minutes, seconds to decimal degrees conversion, and vice-versa
•Logarithmic functions : log, 10**x, ln, e**x
•Summation Σ+, mean, standard deviation
•Other functions : Y**x,1/x, √x, π, FRAC, INT, ABS, %
•Display : LED, 10 significant digits (8 + 2 digit exponent in scientific notation), 10-99 to 10+99
•Memory : 4 register stack, stack roll down, X-Y interchange, 10 memory registers with register math
•Optional thousands separator

What’s New

Version 2.16

- Update for iOS 12.3.1.

Ratings and Reviews

4.7 out of 5
14 Ratings

14 Ratings

sonarman ,

I wish I’d found it sooner!

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.

RandyAtKC ,

Old HP-25 user

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...

brianrhill ,

Amazing Rendition

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.


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.


Technology Man IR
48.9 MB

Requires iOS 8.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
Rated 4+
Copyright (©) 2010-2019 Stephen O. Lidie


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