# GO-25 SciRPN

> HP-25C programmable scientific calculator simulation with RPN and 99 program steps. (iPhone/iPad app by Steve Lidie.)

- Source: https://appshunter.io/ios/app/go-25-scirpn/id408249517 (this page in markdown: same URL + `.md`)
- Developer: [Steve Lidie](https://appshunter.io/developer/1869780159)
- Category: Utilities, Productivity
- Price: $4.99
- Rating: 4.70/5 from 23 App Store ratings · 35 written reviews indexed
- Age rating: 4+
- Requires: iOS 16.0 · 18 MB
- Languages: American English
- Released: 2011-03-20
- Data updated: 2026-08-17
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/go-25-scirpn/id408249517/reviews.md

## What is GO?

GO-25 SciRPN simulates the venerable HP-25C Programmable Scientific Calculator from 1976. Virtually indistinguishable from the real item in operation, GO-25 is a powerful yet simple retro calculator.

• RPN (Reverse Polish Notation)
• 10-digit LED calculator display, 10-99 to 10+99
• Four stack registers with roll down
• Ten storage registers with arithmetic memory operators
• Math, trigonometric, polar/rectangular, sexagesimal/decimal, logarithmic, statistical, power and other miscellaneous functions
• Programmable, with annotated program listing, and memory for 99 program steps
• Library of Sample Programs
• Fast, slow or single step program execution
• Program import via pasteboard or from other Apps
• Program export via printer, email, pasteboard or to others Apps
• iTunes program File Sharing
• Two additional windows with views of:
	◦ stack/storage registers
	◦ keystroke log
	◦ program source code
	◦ program documentation
• Copy-from and Paste-to the calculator display
• Simple Paper Tape annotations

## Key features

- RPN input
- 10-digit LED display
- Four stack registers
- Ten storage registers
- Extensive math functions
- 99-step programmability
- Program import/export

## Chart rankings

- #192 in Top Paid · Utilities (US App Store)

## Recent user reviews (10 of 35)

All indexed reviews: https://appshunter.io/ios/app/go-25-scirpn/id408249517/reviews.md

### 2/5 — Huh - looks like a phone app

*2026-05-15, version 5.1*

This looks like something that was created for the iPhone and just ported without any consideration for screen size - I’d like to see this 2-4 times its size if I’m on a desktop

### 5/5 — Faithful

*2025-10-13, version 5.1*

I used a HP25c in 1970’s. This is a very faithful emulation that I’ve used for many years.

### 5/5 — The best HP25c

*2024-12-23, version 5.1*

The best HP25c emulator I could find.

### 5/5 — My favourite calculator.

*2024-05-27, version 5.0*

I have this on my iPhone. I purchased a HP-25 in 1978 and used it through the final year of school, through university and into my teaching career. I only stopped using it when the battery pack died then I discovered this app. Bliss! Once you learn RPN you can never go back. I love this app - it is identical to the real thing.
My only bugbear is "How do I turn off the Stack/registry screen?" I just seem to randomly tap the screen for minutes until it randomly turns off. There must be an easier way. Help.

### 5/5 — Great app!

*2024-04-29, version 4.6.3*

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

### 4/5 — Slow button response resolved

*2021-03-30, version 4.3*

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!

### 5/5 — Old HP-25 user

*2019-03-25, version 2.15*

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...

### 5/5 — I wish I’d found it sooner!

*2018-09-08, version 2.13.4*

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.

### 5/5 — Problème maj 2.13

*2018-09-08*

Super appli que j’utilise depuis longtemps, mais la mise à jour 2.13 a réduit la taille de la hp25 et la met dans le coin haut gauche.
Ce serait super de corriger ce bug. Y compris sur la hp21...

**Developer response:** Bug fixed for both the 21 and 25 emulations - sorry about that.

### 5/5 — Jcc3rd RPN user

*2016-05-10, version 2.4.21*

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.

## Frequently asked questions about GO

### What is GO-25 SciRPN?

GO-25 SciRPN is a mobile application that simulates the functionality of the vintage HP-25C Programmable Scientific Calculator. It aims to replicate the original device's operation and features, including its RPN input method and extensive mathematical capabilities.

### What are the key features of this calculator app?

The app features Reverse Polish Notation (RPN) input, a 10-digit LED display, four stack registers, ten storage registers, and a wide array of math, trigonometric, and statistical functions. It also supports programming with up to 99 steps and allows for program import and export.

### How much does GO-25 SciRPN cost?

Based on the provided information, this application is a paid app. There are no mentions of in-app purchases or advertisements, indicating a one-time purchase model.

### What kind of programs can I create with GO-25 SciRPN?

You can create programs for various calculations using the app's 99 program steps. This includes mathematical, trigonometric, polar/rectangular conversions, sexagesimal/decimal conversions, logarithmic, statistical, and power functions, among others.

### How can I share or import programs with this app?

Programs can be imported into the app via the pasteboard or from other applications. They can also be exported via printer, email, pasteboard, or to other apps. Additionally, iTunes File Sharing can be used for program management.

## Version history (last 5 releases)

### 26.5.1 — 2026-06-11

- Repair broken icon and update documentation.
- Update to Apple OS versions 26.5.1.

### 26.5 — 2026-05-31

- ENG display format & other bug fixes and enhancements.
- Provide a complete PDF hardcopy of the HTML user manual, including an index.
- Minimum macOS version now 13.0 (Ventura).
- Minimum iOS / iPadOS / tvOS versions now 16.0.
- Update to Apple OS versions 26.5.

### 5.1 — 2024-09-17

- Update for iOS 18.0, iPadOS 18.0, tvOS 18.0, macOS 15.0.

### 5.0 — 2024-05-15

- New Settings option, Auxiliary View Assist, enables draggable buttons for quickly opening / closing the stack window.
- New Settings collection, Accessibility, groups High Visibility Display, Magnify Calculator and Auxiliary View Assist.
- The Settings option Auto-On now defaults to YES.
- Remove vestigial iOS 9 Settings option that assisted in migration from iCloud Documents to iCloud Drive for program storage.
- Battery power level reporting has changed in iOS, iPadOS and macOS: adjust power level monitoring algorithm to compensate.
- Bug fixes, miscellaneous improvements and internal modernization.
- Refresh documentation.
- Update for iOS 17.5, iPadOS 17.5. tvOS 17.5, macOS 14.5.

### 4.6.3 — 2024-03-09

- Fixed: problem with program entry.
- Miscellaneous improvements recommended for everyone.
- Update for iOS 17.4, iPadOS 17.4.

## Apps similar to GO

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [RPN-97 Pro](https://appshunter.io/ios/app/rpn-97-pro/id816249055) | 4.9 (11) | $4.99 | Utilities |
| [RPN-67 SD](https://appshunter.io/ios/app/rpn-67-sd/id1109722386) | 4.6 (16) | $3.99 | Utilities |
| [AutoMathic](https://appshunter.io/ios/app/automathic/id386491861) | 5.0 (2) | $1.99 | Utilities |
| [RLM-10CX](https://appshunter.io/ios/app/rlm-10cx/id6466089794) | 5.0 (1) | Free | Utilities |
| [RPN-25 CE](https://appshunter.io/ios/app/rpn-25-ce/id1529311398) | 4.6 (9) | $2.99 | Utilities |
| [CalcMe Calculator](https://appshunter.io/ios/app/calcme-calculator/id1662123996) | 5.0 (1) | $1.99 | Utilities |

## More apps by Steve Lidie

- [GO-21 SciRPN](https://appshunter.io/ios/app/go-21-scirpn/id327651563)
- [Photo Gopher](https://appshunter.io/ios/app/photo-gopher/id662735770)
- [Solar Coaster](https://appshunter.io/ios/app/solar-coaster/id1218422388)
- [GO-29 SciRPN](https://appshunter.io/ios/app/go-29-scirpn/id1472811056)

All apps by Steve Lidie: https://appshunter.io/developer/1869780159

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-17.*