# RPN 15C — HP 15C scientific calculator

> HP 15C scientific calculator (iPhone/iPad app by Guglielmo Pasa.)

- Source: https://appshunter.io/ios/app/rpn-15c/id6827122699 (this page in markdown: same URL + `.md`)
- Developer: [Guglielmo Pasa](https://appshunter.io/developer/417854438)
- Category: Education, Utilities
- Price: $9.99
- Age rating: 4+
- Requires: iOS 16.0 · 24 MB
- Languages: American English
- Released: 2026-11-05
- Data updated: 2026-11-10

## What is RPN 15C?

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.

RPN 15C is a new simulator written from the calculator's owner's handbook, every worked example of the handbook serving as a test: it computes as the 15C does, to its ten digits, with its rounding, its stack and its error messages.

THE CALCULATOR
• RPN with the four-level stack, LAST X, the storage registers, the Index register and register arithmetic
• 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: the stack holds them, and nearly every function works on them
• Matrices up to 8 × 8 (64 elements in all): arithmetic, inverse, transpose, determinant, linear systems, norms, residuals, complex matrices
• SOLVE: the roots of your own functions
• Numerical integration of your own functions, with its uncertainty
• Statistics: mean, standard deviation, linear regression and estimation, correlation, permutations and combinations, random numbers
• Programs of up to 448 lines: labels, subroutines, conditional tests, flags, loops with DSE and ISG, indirect addressing, single-step and pause
• The calculator's own memory: 67 registers shared by data, programs and matrices

THE APP
• The calculator's memory stays, as on the 15C (Continuous Memory): close the app, come back later, everything is where you left it
• Turn the calculator over: its back plate, a reference table of the error messages, the MATRIX and TEST numbers and the statistics registers
• Copy the number in X with all its digits, paste numbers from the clipboard
• Decimal point or decimal comma
• Hardware keyboard on iPad, iPhone and Mac; on the Mac, the window takes the calculator's shape and zooms in steady steps
• Works fully offline, no account, no ads, no tracking

The app contains no HP software. HP and HP 15C are trademarks of HP Inc. This app is an independent project and is not affiliated with or endorsed by HP.

## Is RPN 15C safe?

Not enough ratings yet to assess RPN 15C.

## Is RPN 15C legit?

RPN 15C appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for RPN 15C is 75 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 2 releases)

### 0.1.1 — 2026-11-06

• In landscape, when the calculator fills the screen, the display is larger.
• The white band under the keyboard now meets the case evenly.
• Save Program… and Load Program… (the menu; on the Mac, the File menu): the program to a .15c file and back, the format of Torsten Manz's HP-15C Simulator.
• In landscape the calculator now starts at its own proportions (Layout ▸ Original Proportions).

### 0.1.0 — 2026-11-05

No release notes.

## More apps by Guglielmo Pasa

- [DjVu Reader](https://appshunter.io/ios/app/djvu-reader/id417854435)
- [UniReader: Multi-Format Reader](https://appshunter.io/ios/app/unireader-multi-format-reader/id6759504986)
- [RPN 50g](https://appshunter.io/ios/app/rpn-50g/id6811794850)
- [RPN 48](https://appshunter.io/ios/app/rpn-48/id6814120753)
- [Ma Marge](https://appshunter.io/ios/app/ma-marge/id6814141541)
- [RPN 12C](https://appshunter.io/ios/app/rpn-12c/id6826865969)

All apps by Guglielmo Pasa: https://appshunter.io/developer/417854438

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-11-10.*