RPN 48

The HP 48 is the calculator of a generation of engineers, physicists and students: the 48SX of 1990 brought RPN, RPL programming, units, symbolic algebra and graphing into one machine, the 48GX of 1993 added the equation library, the solver applications, more memory and a faster processor. Thirty years on, many still keep one on their desk — and this app puts one in your pocket.

RPN 48 is not an imitation: it emulates the calculator's hardware — the Saturn processor, the memory controllers, the 131×64 display, the keyboard, the timers — and runs HP's original ROM, so it behaves exactly as the real machine: every function, every menu, every flag, every quirk.

THE CALCULATOR
• RPN with the four-level stack (and unlimited stack depth), or algebraic entry, at your choice
• Symbolic algebra: expressions, simplification, derivatives, integrals, Taylor series, equation solving; exact rational and integer arithmetic
• Scientific calculator: complex numbers, vectors and matrices, statistics and regressions, unit conversions with dimensional analysis, base conversions (BIN/OCT/HEX), numeric solver, financial (TVM) calculations, dates and times
• Graphing: function, polar, parametric, conic, differential equation, statistics and 3D plots, with zoom and trace
• The 48G series' Equation Library with 300 equations of physics and engineering, with units
• Programmable in RPL: your programs run as on the real machine

THE APP
• Both models: the HP 48GX (ROM revisions R and P, the 48G series' 128 KB) and the HP 48SX (ROM revisions J and E), each at its own speed and with its own memory
• Your calculator's memory stays: close the app, come back later, it is exactly where you left it
• HP's manuals (Quick Start Guide, User's Guide, Advanced User's Reference) can be downloaded into the app and read next to the calculator; the app remembers your page
• Hardware keyboard support on iPad and iPhone
• Works fully offline, no account, no ads, no tracking

ABOUT THE ROM
The app contains no HP software. On first launch you pick a model and its ROM image is downloaded from hpcalc.org, the community archive where HP allowed the HP 48 ROMs to be published in 2000, exactly as you would with a browser; the image is then kept on your device.

HP, HP 48, HP 48SX and HP 48GX are trademarks of HP Inc. This app is an independent project and is not affiliated with or endorsed by HP.