RPN-55 SD

Willy Kunz · Productivity

5.0 8 ratings $1.99
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Chart standing · US

Top Paid Productivity
#94
Best #94

Ratings breakdown · US

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5★ 100% 8
4★ 0% 0
3★ 0% 0
2★ 0% 0
1★ 0% 0

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About

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. Features: • 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 · 3.3

• Improved compatibility with iPhone Air and iOS 26.

Details

DeveloperWilly Kunz
ReleasedJul 2019
UpdatedOct 2025
Version3.3
Size17.7 MB
RequiresiOS 12.0 or later
Age rating4+
LanguagesEnglish
Price$1.99
Categories ProductivityUtilities
Bundle IDRPN-55-SD