RPN 50gThe RPN simulators
Five of HP's classic calculators on iPhone, iPad and Mac: the HP 12C and HP 17bII+ financial calculators, the HP 15C, HP 32SII and HP 35s scientific ones. Each was written again from HP's own manuals and is checked against every worked example in them, so it computes as the calculator does — to its digits, with its rounding, its messages and its prompts.
The five calculators
| App | Calculator | For | Checks from the manual |
|---|---|---|---|
| RPN 12C | HP 12C (1981), 10 digits | finance in RPN: loans, cash flows, bonds, depreciation, dates, keystroke programs | 239 |
| RPN 17bII+ | HP 17bII+ (2003), 12 digits | finance with menus: TVM, cash flows, bonds, statistics, dates and the equation Solver, in ALG or RPN | 630 |
| RPN 15C | HP 15C (1982), 10 digits | science in RPN: complex numbers, matrices, SOLVE, integration, keystroke programs | 465 |
| RPN 32sII | HP 32SII (1991), 12 digits | science in RPN: fractions, the equation list, SOLVE and integration, bases, keystroke programs | 1066 |
| RPN 35s | HP 35s (2007), 12 digits | science in RPN or ALG: equations, SOLVE and integration, complex numbers and vectors, constants, keystroke programs | 813 |
The checks are the worked examples and application programs of each calculator's manual, run against the simulator: results, rounding and messages must match. For the graphing calculators, which run HP's own firmware, see the emulators: RPN 50g, RPN 49G and RPN 48.
Written from the manuals, checked against them
A simulator writes the calculator again instead of running HP's code. Done carelessly it is a look-alike that rounds differently and accepts what the real one refuses. These were written from HP's owner's handbooks and user's guides, page by page, and every worked example in them — the application programs included — became a test: over three thousand in all. They compute to the calculator's own digits, ten on the 12C and 15C, twelve on the others, with its rounding, its error messages and its prompts.
They contain no HP software and need no ROM: they are ready at first launch, work offline, and keep their memory as the calculators do (Continuous Memory). HP's manuals for each one can be downloaded in the app and read next to the calculator.
The calculators, and where they are today
The HP 12C has been made since 1981 and still is; the HP 15C came back as a Collector's Edition in 2023. The HP 32SII was made from 1991 to 2002 and the HP 35s, introduced in 2007, is no longer in HP's catalogue: RPN 32sII and RPN 35s bring them back, on the screen you always carry.
Which one do you want?
Financial: the HP 12C is the keystroke calculator of bankers and of the CFA and CFP exams, fast once you know it; the HP 17bII+ names every value on its display, has a menu for every calculation and an equation Solver for the rest, in ALG or RPN.
Scientific: the HP 15C packs complex numbers, matrices, SOLVE and integration in the Voyager format; the HP 32SII is the classic RPN calculator of the 1990s, with fractions, menus and an equation list; the HP 35s adds algebraic entry, a two-line display, vectors and the physical constants.
Frequently asked
Do the simulators contain HP's ROM?
No. They contain no HP software at all: each calculator was written from HP's manuals, its worked examples serving as tests. Nothing has to be downloaded to use them; the network is used only for a manual you ask for.
Are the results the same as on the calculator?
That is what the tests check: the manuals' worked examples and application programs, with the calculator's digits, rounding and error messages. If you find a difference, write to info@pasahome.org with the keystrokes.
Which devices do they run on?
iPhone, iPad and Mac; an Android version is in preparation.