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GO-25 SciRPN

By BigCatOs

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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 6.0 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 in Version 2.4.21

- To H.MS small number fix.


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iPad Screenshot 1
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Customer Reviews

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.

Great Emulation

Those of us who could not afford the flagship HP calculators in the 1970's remember very well the HP-21 and HP-25 series that saved the day for poor college students. I have used this app for several years as my day-to-day go to calculator on my iPad and iPhone. It's a GREAT emulation, with a few more bells and whistles to boot than the original hardware. Sadly my original HP-25 on-off switch and battery gave up the ghost long ago, but having this app is a great nostalgic substitute!

GO-25 SciRPN
View In iTunes
This app is designed for both iPhone and iPad
  • $1.99
  • Category: Utilities
  • Updated:
  • Version: 2.4.21
  • Size: 12.2 MB
  • Language: English
  • Seller:

Compatibility: Requires iOS 6.0 or later. Compatible with iPhone, iPad, and iPod touch.

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