i41CX+ is an advanced programmable and expandable RPN scientific calculator with a virtual thermal printer/plotter and workstation-class CAS capabilities that is far beyond a mere replica of the original. In addition to being functionally equivalent to the world-renowned HP-41CX and providing access to its entire library of modules and programs, i41CX+ is enhanced with iOS and hardware features, keyboard overlays, rich set of import and export capabilities, traditional and upbeat diverse set of skins, complete color control, iCloud support, and much more.

The i41CX+ CAS is a full implementation of REDUCE. It's like having Mathematica or the computational engine of Wolfram Alpha in your pocket and, best of all, it runs natively so no internet connection is required. The CAS is fully programmable and provides the ability to reuse previous results in computations. Moreover, the CAS has full access to the calculator registers so it is possible to combine RPN programs with CAS programs.

This is the finest and most powerful scientific/engineering/financial calculator for iOS devices bar none.

• RPN logic with a 4 element deep memory stack
• 319 main and 600 extended memory registers
• Over 400 built-in functions, including over 100 functions created specifically for i41CX+
• Time, calendar, alarm, and stopwatch functions
• Four module ports provide access to HP-41 expansion pacs
• Rich set of functions and algorithms: numerical, mathematical, statistical, complex, matrix, numerical integration, curve fitting, solutions to equations, and much more
• Powerful, flexible, and programmable Computer Algebra System (CAS) supporting symbolic, arbitrary precision, scalar, vector and matrix algebra calculations, 2D/3D plotting, and much more
• Full-screen text editor with configurable font style and size, color scheme, a user configurable macro keyboard, and a numerical keyboard
• 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 - virtually unlimited number of lines
• User definable keyboard
• Ability to operate the calculator using a Bluetooth keyboard
• Device integration: external display mirroring, copy and paste, in-app mail, system keyboard, GPS, accelerometer, digital compass, time and date synchronization, AirPrint, and much more
• Virtually unlimited data and program storage capacity using the device's flash memory for local storage
• Import/export data, programs, overlays, modules, etc. via the web, email, and iTunes file sharing
• iCloud syncing of files and preference settings
• iOS 8 Notification Center widget
• 43 available keyboard overlays and support for user created overlays
• Sound support including synthetic tones and interface sounds
• Support for calculator skins and optional mini stack display
• Adjustable calculator speed, sound volume, and display colors
• Usage & Examples table with usage tips and examples
• Quick Reference Guide of all built-in functions
• CAS Quick Reference with all built-in functions, operators, switches, and packages
• Beautiful and clean user interface

• Support for printing, plotting, graphics, and special characters
• User configurable and programmable print color
• Export printer output via email, clipboard, or AirPrint
• Ability to save a JPEG image of the paper roll to the device's photo album

A comprehensive FAQ and Mini-Manual are available at Please don't hesitate to use the "Contact Us" link there if you cannot find the answers or information that you seek. Thank you.

What’s New

Version 7.6.0

• Internal optimizations.

Ratings and Reviews

4.7 out of 5
58 Ratings

58 Ratings

EyeballDoc ,

Better than the original

The HP41cx+ calculator uses Reverse Polish Notation (RPN) which is an absolute must for me. The HP41cx+ program by Antonio Lagana faithfully replicates the original HP41 and adds all the bells and whistles which were later developed for the calculator all in one package. Not only do you get the fabulous HP calculator but you get all the overlays, the ability to run a tape with graphics, the extra memory, all the programming functions, the extreme precision and RPN. This program yields an excellently fully functioned, easy to use calculator. It is a joy to use!

owndao ,

Great do-everything calculator

This is the calculator that got me through engineering. Even better than the original with a built-in printer and CAS features. My only complaints are that the loading of ROM packs and overlays leaves much to be desired and the manual offers more of a continuous feature advertisement than a understanding of pages, the strange behavior when loading modules. The help is a mixed up mess when you consider docs for the simulation, docs for the calculator, and docs for the ROM packs are all to be found in different places and accessed different ways and are sometimes old versions or dependent upon other modules. But when it comes down to the number crunching this calculator really shines.
It leaves me with the feeling of what a wonderful calculating device the developer could put together by taking the best ideas from this project and eliminating the irritating peculiarities of the HP41C. Perhaps I’ll stumble upon a way to access CAS and the I41CX-MATH module.
It’s time to scrap old design traditions and think a bit about designing a tool to do what the user needs. A bit of thinking ala SpaceX-style could produce a much more usable tool than the emulation of a product of 40 years ago.

AI Architect ,

Physicist at Large

I cannot rave enough about the i41CX+ app. I have a real hp41CV from college and grad school days (mint condition). I use it rarely so that it doesn't wear out.

First HP I owned was a model 67 and I was hooked. This 41cx app keeps the entire 41 product and accessories, and then some, in my pocket. Couldn't be more happy with the performance and user experience. Well done !! Please keep it going. It's bad enough HP has abandon these gems. I'd like to know that this app will remain for years to come. Thanks for the great work.


Antonio Lagana
298.8 MB

Requires iOS 9.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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