# GO-21 SciRPN

> Utilities

Canonical page: [https://chrome-stats.com/d/id327651563](https://chrome-stats.com/d/id327651563)

## Overview

- **ID:** `id327651563`
- **Platform:** Apple
- **Type:** Apple app
- **Status:** Available
- **Publisher:** Steve Lidie
- **Category:** Utilities
- **Rating:** 4.90 / 5 (13 ratings)
- **Version:** 26.5.1
- **Last updated:** 2026-06-11
- **First published:** 2009-08-28
- **Size:** 15 MB
- **Data as of:** 2026-09-07
- **Store listing:** [Apple App Store](https://apps.apple.com/us/app/go-21-scirpn/id327651563)
- **Website:** [http://www.bigcatos.com/BigCatOs/go-2x-scirpn/go-21.html](http://www.bigcatos.com/BigCatOs/go-2x-scirpn/go-21.html)
- **Privacy policy:** [http://www.bigcatos.com/BigCatOs/BigCatOSPrivacyPolicy.pdf](http://www.bigcatos.com/BigCatOs/BigCatOSPrivacyPolicy.pdf)

## Description

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

## Rankings

- #288,661 — Overall

## Similar extensions and apps

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- [RPN-45 SD](https://chrome-stats.com/d/id509923051) — 4.30 / 5
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- [RPN-25 CE](https://chrome-stats.com/d/id1529311398) — 4.60 / 5
- [RPN-35 SD](https://chrome-stats.com/d/id956224485) — 4.40 / 5
- [Simple RPN](https://chrome-stats.com/d/id6771959257) — 5.00 / 5
- [RPN 28x Calc](https://chrome-stats.com/d/id529927583) — 5.00 / 5
- [JRPN 15C](https://chrome-stats.com/d/id6484504019) — 5.00 / 5

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Source: [Chrome-Stats](https://chrome-stats.com/d/id327651563)