RPN 48

RPN 48

HP 48GX and 48SX calculator

1 ratings
1 review
$5.99

Details

Released
September 23, 2026
Updated
November 9, 2026

Features

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iphone
ipad
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About

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 GitHub, where the app keeps a copy of the package published on hpcalc.org, the community archive where HP allowed the HP 48 ROMs to be published in 2000; 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.
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What's New in RPN 48

0.3.0

November 9, 2026

• The paper roll (the menu ▸ Show Paper Roll; on the Mac, Calculator ▸ Show Paper Roll, ⇧⌘P): beside the calculator on an iPad, as a sheet on an iPhone, a window of its own on the Mac, which holds against the calculator's side when dropped there. The last 500 lines are kept. • Each operation is written on it as on a printing calculator: the command line and the key (or the menu label) on the left, level 1 on the right, as the display shows it. ⋯ ▸ Log Calculations turns it off and on. • What the calculator prints (PR1, PRST, PRVAR, PRLCD…) comes out on the roll, as on the HP 82240B infrared printer. • Share ▸ Copy, Share Text, Share PDF, Save as PDF… (Mac) and Print…: A4 or Letter pages with the calculator's name and the date. On the Mac, File ▸ Save Paper Roll as PDF… and Print Paper Roll… (⌘P), the roll's window shown or not. • On the Mac, the manual's window holds against the calculator's side too, beyond the roll when both are on the same side. • Sync Clock to System Time (in the menu; on the Mac, Calculator ▸ Sync Clock to System Time), on by default: the calculator's TIME and DATE are set to the device's clock at launch and whenever the app comes back to the front. • A hardware keyboard's letters work: each one presses the key that carries it in alpha mode (S is SIN, T is COS…); α first (Tab) to type it, twice to lock.

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User reviews

WOW!! This HP48SX user is impressed

I use an actual 1991 vintage HP 48SX every day at work (I bought it new back then). This app on my iPhone 15 Max, looks and acts EXACTLY like the calculator on my desk. If you’re an HP 48 fan, spend the five dollars to get this program and you won’t be disappointed.

Response from developer

Thank you for your kind words. And happy that you like it! I hope the options to com will satisfy you also.

Developer apps