# i41CX — RPN Calc

> RPN scientific calculator with extensive functions and programmability, expandable via in-app purchases. (iPhone/iPad app by Antonio Lagana.)

- Source: https://appshunter.io/ios/app/i41cx/id292619450 (this page in markdown: same URL + `.md`)
- Developer: [Antonio Lagana](https://appshunter.io/developer/289068868)
- Category: Productivity, Utilities
- Price: $7.99 with in-app purchases
- Rating: 4.60/5 from 45 App Store ratings · 126 written reviews indexed
- Age rating: 4+
- Requires: iOS 9.0 · 371 MB
- Languages: American English
- Released: 2008-10-16
- Data updated: 2026-08-31
- Monetization: free with in-app purchases
- User reviews in markdown: https://appshunter.io/ios/app/i41cx/id292619450/reviews.md

## What is i41CX?

i41CX is the same powerful advanced programmable RPN scientific calculator as the highly acclaimed i41CX+ but without the latter’s incredibly advanced capabilities such as the printer, expansion, CAS, etc.  It is functionally equivalent to the world-renowned HP-41CX and inherits all of the i41CX+ usability features including extremely responsive and animated key clicks, audible key feedback sounds, optimally spaced keys for accurate input, traditional and upbeat modern diverse set of skins, etc.

If you are looking for a powerful programmable RPN scientific calculator but don’t need all of the capabilities of i41CX+ then i41CX is for you.  And best of all, if you ever decide that you need the more advanced capabilities of i41CX+ you can enable them using secure in-app purchases right within the app!

FEATURES:
• RPN logic with a 4 element deep memory stack
• 319 main and 124 extended memory registers
• Over 300 built-in functions, including nearly 100 functions created specifically for i41CX
• Time, calendar, alarm, and stopwatch functions
• Rich set of functions and algorithms: numerical, mathematical, statistical, and much more
• Access to the entire HP-41 library of solutions for science, mathematics, statistics, engineering, business, financial, surveying, medicine, real estate, and many other domains
• Programmable - Over 2000 lines
• User definable keyboard
• Ability to operate the calculator using a Bluetooth keyboard
• Device integration: external display mirroring, copy and paste, GPS, accelerometer, digital compass, time and date synchronization, and much more
• iOS 8 Notification Center widget
• Sound support including synthetic tones and interface sounds
• Support for calculator skins and optional mini stack display
• Adjustable sound volume and display colors
• Usage & Examples table with usage tips and examples
• Quick reference guide of all built-in functions
• Beautiful and clean user interface

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A comprehensive FAQ is available at http://alsoftiphone.com/i41CX.  Please don't hesitate to use the "Contact Us" link there if you cannot find the answers or information that you seek.  Thank you.

## Key features

- RPN logic with 4-element stack
- 319 main and 124 extended memory registers
- Over 300 built-in functions
- Programmable up to 2000 lines
- User-definable keyboard
- Bluetooth keyboard support
- Device integration features

## Pricing and in-app purchases

Base price: $7.99.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| i41CX+ Features Upgrade | $17.99 | one-time |
| CAS Upgrade | $7.99 | one-time |
| Printer Upgrade | $3.99 | one-time |
| Overlays Upgrade | $2.99 | one-time |


## Recent user reviews (10 of 126)

All indexed reviews: https://appshunter.io/ios/app/i41cx/id292619450/reviews.md

### 5/5 — Indispensable

*2026-01-12*

Une réplique merveilleuse de la HP41CV

### 5/5 — Perfeita

*2024-09-29*

Perfeita, dunciona exatamente como minha antiga HP41C!

### 5/5 — Simply the best HP41 emmulator

*2024-08-13*

I've been using my original HP41CV since ~ 1980, and just love RPN and the functionality and the history of this groundbreaking calculator. I use an emmulator on my PC, but was challenged finding a good emmulator while on other mobile platforms. This is the first app I purchased once moving to IPhone in 2017 and I it's the only calculator I use. Works just like the original and always brings me great memories, making me smile every time I use it.

### 5/5 — So good I retired my HP-41CV!

*2024-06-14*

This is a great program! The interface is so well designed and uses all of the available screen space so that the numbers are readable for this old timer. In the HP tradition, this app exceeds expectations in both quality and performance.

### 5/5 — Genial. Igual que la auténtica.

*2024-03-28, version 7.6.14*

Para cualquiera que la tenga o la añore. Como llevarla encima.

### 5/5 — Extraordinario. Viaje a 1986. Saludos.

*2024-01-08, version 7.6.14*

Me gusta mucho.

### 1/5 — Peggiorato

*2023-11-25, version 7.6.13*

Prima dell’aggiornamento era super 
Adesso non si riesce a togliere il fastidiosissimo “ritorno” dei valori di input sul display . Roba da epilessia !!!!!

Applicazione cancellata, con rammarico

### 5/5 — Fantastica!

*2023-11-06, version 7.6.12*

La migliore calcolatrice programmabile di sempre che gira a meraviglia sul vostro iPhone!

### 5/5 — Masterful reincarnation of the original !

*2022-10-02*

Well done! $/feature/functionality it’s like buying a hand held super computer. Holy cow! Not to mention throw-back value for boomer generation :)

### 5/5 — This is a great app!

*2022-01-26*

I have been using HP calculators since I bought a HP45 in about 1973

With HP mostly out of the Scientific RPN calculator area this app fills the need!

Makes me miss my HP41CV I had (that died after many years of heavy use). 

Super customer service as well.

## Frequently asked questions about i41CX

### What does this app do?

This app provides a powerful RPN scientific calculator experience, functionally equivalent to the renowned HP-41CX. It offers a deep memory stack, a vast array of built-in functions, and extensive programmability, making it suitable for complex calculations in various scientific and engineering domains.

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

Key features include RPN logic with a 4-element stack, 319 main and 124 extended memory registers, over 300 built-in functions, and the ability to program up to 2000 lines. It also supports a user-definable keyboard, Bluetooth keyboard operation, and various device integrations.

### How much does this app cost?

The app is free to download and use with its core RPN calculator functionality. However, more advanced capabilities, such as those found in the i41CX+ version, can be unlocked through secure in-app purchases.

### What kind of users is this app designed for?

This app is designed for users who require a powerful and programmable RPN scientific calculator. It is particularly useful for students, engineers, scientists, and professionals who need advanced calculation capabilities and appreciate the efficiency of RPN logic.

### Can I use this app with a physical keyboard?

Yes, the app supports operating the calculator using a Bluetooth keyboard. This feature enhances usability for users who prefer physical input methods for extensive calculations or programming.

## Version history (last 5 releases)

### 7.6.19 — 2026-01-28

• Fixed bug introduced in 7.6.18

### 7.6.18 — 2026-01-27

• iOS 26 compatibility

### 7.6.17 — 2025-08-20

• Minor bug fixes

### 7.6.16 — 2024-10-06

• Minor bug fix

### 7.6.15 — 2024-04-13

• Minor bug fixes

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## More apps by Antonio Lagana

- [i41CX+](https://appshunter.io/ios/app/i41cx-plus/id289068865)
- [iCAS](https://appshunter.io/ios/app/icas/id394637176)

All apps by Antonio Lagana: https://appshunter.io/developer/289068868

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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 2026-08-31.*