GO-21 SciRPN

Name: GO-21 SciRPN
Price: 2.99 USD
Rating: 4.9 (12 reviews)
Author: Steve Lidie

By: Steve Lidie

Utilities

▶

Features & Capabilities

GO-21 SciRPN simulates the venerable HP-21 Pocket Scientific Calculator from 1975. Virtually indistinguishable from the real item in operation, GO-21 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 • One storage register with arithmetic memory operators • Math, trigonometric, polar/rectangular, logarithmic, power and other miscellaneous functions • One additional window with views of: ◦ stack/storage registers ◦ keystroke log • Copy-from and Paste-to the calculator display • Simple Paper Tape annotations

User Growth & Download Statistics

App

By:

Steve Lidie

Rating:

4.90

(12)

Version:

26.5 Last updated: 2026-05-31

Version code:

886052330

Creation date:

2009-08-28

Compatible devices:

Size:

19.61MB

Price:

2.99

URLs:

Website ,Privacy policy

Full description:

Source:

Apple Apps Store

Data ingested on:

2026-06-06

Compare stats and ranking:

Ranking

# 341,507 ▼ 1,335

For Developers

Monetize with App Pass Boost with Extension Booster

Contact the developer

Chrome-Stats does not own this Apple app. Please use these information below to contact the Apple app developer.

Developed by:

Steve Lidie

Apple Apps Store

https://apps.apple.com/us/app/go-21-scirpn/id327651563

Website:

http://www.bigcatos.com/BigCatOs/go-2x-scirpn/go-21.html

User Reviews

I bought my HP-21 shortly after i saw it in Machine Design magazine in 1976. From then on it became my constant companion until appx 1995 or so when it gave up the ghost and would no longer illuminate. Much later on I was overjoyed to find an e-version replica of my faithful pocket resource, though he was no longer needed after I retired from field work. Today I have switched to Android apps and regret that I cannot find a replica of this trusty device,,,,, and would like to ask IF THERE IS ONE (?) or one under development? All iOS products havre become too expensive and unreliable !

by Er*****, 2022-06-22

Many thanks for giving me the opportunity to use this RPN calculator. I bought my very first HP 21 C in 1972 when studying at Polytechnic School of Cameroon. 50 years later, I am still very happy and proud using RPN devices and programming Common LISP.

by Rb*****, 2022-06-15

To me, the value of this app (and all the other RPN apps that I have) is the authenticity of them. Otherwise, there are a gazillion calculators with different sized displays out there with RPN. Instead of making the X view high visibility, why not enlarge the calculator itself to be full screen (even getting rid of the stack view optionally) Then I’ll go back to 5 stars again which otherwise this app absolutely deserves.