RPN-55 SD by CuVee Software (iPhone)
Released: Jul 3, 2019
Version: 2.4
Size: 17 MB
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Ranking - Productivity (iPhone)


CuVee Software
Screenshot #1
RPN-55 SD is the first photo-realistic simulation for the iPhone of Hewlett-Packard's low-cost alternative to the famous HP-65 programmable scientific calculator. Produced from 1975 through 1977, it was the "Merlin" member of the classic HP calculator series, priced at $395. HP claimed that it featured "(...) more pre-programmed functions than any other scientific pocket calculator in the world."

A main feature of the HP-55 was a crystal-controlled 100-hr digital timer with the ability to store times while the timer was running and later recall them. On RPN-55 SD the timer may also act as a 12-hr or 24-hr clock, including date and weekday display.

While the simulator works just like the original calculator – except being much faster and having twice the program memory – you can turn on extended features to make it even more enjoyable to use.

RPN-55 SD comes complete with original HP programs built in.


• Photo-realistic look-and-feel
• Vintage mode or Extended mode
• Programmable (99 steps), conditional branching
• Insert and delete steps with automatic address correction
• Delete range of steps
• Subroutines (4 levels)
• 20 registers, "continuous", with unrestricted store/recall arithmetic
• "Live" register view
• Program listing view
• Program library view
• Store and retrieve any number of programs
• 100-hr timer supporting 10 split times and 12/24-hr clock mode with date
• Swap unit conversions with additional functions, e.g. hyperbolics
• Sharing: e-mail, AirDrop, Dropbox, copy, paste, print
• 112 programs pre-installed

Calculator functions:

• Statistics (linear regression, mean, standard deviation, correlation coefficient, x- and y-estimates)
• Trigonometric functions (degrees, radians, grads)
• Polar/rectangular conversions
• Inverse, square root, logarithm, exponential, pi
• Storage arithmetic (store and recall)
• Percent, absolute, integer, fractional value, round
• Factorial
• Random number
• Unit and hours conversions

Details: cuveesoft.ch/rpn55

What's new in version 2.4
• Improved mail subject when mailing a program as PDF
• New sample program "TVM - Solve for i"
• Visual feedback when reloading programs in file list view

Bug fix:

• GSB command could not be pasted as text in PRGM mode
Our verdict: Meh!
  • = RPN-55 SD has no ratings yet.
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