*** Now Optimized for iOS 8 and 64-bit Devices! ***

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!


  • Functionally equivalent to the world-renowned HP-41CX
  • 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
  • Rich set of functions and algorithms: numerical, mathematical, statistical, and much more
  • Time, calendar, alarm, and stopwatch functions
  • Access to the entire HP-41 library of solutions for scientific, 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
  • Searchable Usage & Examples table with usage tips and examples
  • Searchable Quick Reference Guide of all built-in functions
  • Beautiful and clean user interface optimized for the iOS device's portrait mode screen aspect ratio and to maximize the keypad area while still providing for a full featured scientific keypad