RPN 50gHP 15C scientific calculator for iPhone, iPad and MacRPN 15C — the engineers' scientific calculator since 1982, in RPN, to ten digits.
The HP 15C, introduced in 1982, is the scientific calculator many engineers, scientists and students still consider the finest ever made: complex numbers, matrices, a root finder and numerical integration, in a pocket. RPN 15C puts one on your iPhone, iPad and Mac, with the face, the keyboard and the display of the real thing.
What you get
Computes as the 15C does
A new simulator written from the calculator's owner's handbook, every worked example of the handbook serving as a test: ten digits, with the 15C's rounding, its stack and its error messages.
Scientific functions
FIX, SCI and ENG display; degrees, radians and grads; trigonometric, hyperbolic, logarithmic and exponential functions, powers, factorial and gamma, percentages, polar and rectangular conversions, hours-minutes-seconds.
Complex numbers and matrices
The stack holds complex numbers, and nearly every function works on them. Matrices up to 8 × 8: arithmetic, inverse, transpose, determinant, linear systems, norms, residuals, complex matrices.
SOLVE and integration
The roots of your own functions, and their numerical integrals, with the uncertainty of the result.
Statistics
Mean, standard deviation, linear regression and estimation, correlation, permutations and combinations, random numbers.
RPN and programs
The four-level stack, LAST X, the storage registers, the Index register and register arithmetic; programs of up to 448 lines with labels, subroutines, flags, DSE and ISG loops, indirect addressing — 67 registers shared by data, programs and matrices.
Memory that stays
As on the 15C (Continuous Memory): close the app, come back later, everything is where you left it. Turn the calculator over for its back plate: the error messages, the MATRIX and TEST numbers, the statistics registers.
Keyboard, copy and paste
Copy the number in X with all its digits, paste numbers from the clipboard, decimal point or comma; a hardware keyboard on iPad, iPhone and Mac, where the window takes the calculator's shape.
Offline, private
No account, no ads, no tracking, no data collection. Works fully offline.
In use
Why an HP 15C?
The HP 15C packed into a pocket what used to need a desktop machine: complex arithmetic on the stack, matrix algebra, a root finder and numerical integration, all programmable. RPN — reverse Polish notation, the numbers first and the operation last — is what makes it fast in the hand: no parentheses, no equals key, every intermediate result in view. RPN 15C brings it to the iPhone, iPad and Mac, computing to its ten digits and rounding as it does. Its financial sibling, the HP 12C, is RPN 12C; the HP 48 and HP 50g graphing calculators are RPN 48 and RPN 50g.
About the calculator
The app contains no HP software and needs no ROM: the calculator was written from its owner's handbook alone, its worked examples serving as tests. Nothing is downloaded; everything stays on your device.
The calculator's face is made from a photograph by Pittigrilli, after striegel and Pittigrilli (Wikimedia Commons, CC BY 2.0), its display emptied, its badge and lettering changed.
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