RPN vs Stack RPN Calculator
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
RPN
This app is a faithful simulation of a rare 1974 financial calculator, offering all its original functions with enhanced features like more memory registers and a visual stack display. It's designed for users who appreciate vintage technology and need precise financial calculations.
- Photo-realistic vintage calculator design
- Full HP-70 function simulation
- Animated keys with sound
- Enhanced stack and memory register view
- Cut/copy/paste display value
- Input parameter visual indicators
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RPN-70 SD is a complete simulation of the financial hand-held calculator HP-70 from 1974. It handles loan amortization, saving plans, depreciation, and much more with ease. What users said: "Looks good, all functions you need. Love it!" "This is a beautiful emulation of a very rare HP financial calculator from 1974. Works just like the original but better! Faster, more accurate, with 10 more storage registers, and a popup window lets you see the contents of each stack, financial and storage register. Provides TVM4 functionality for compound interest as well as accumulated simple interest. A true work of art!" Features: • Photo-realistic look based on an existing device • Animated keys with click sound (adjustable volume) • All functions and operations of the HP-70 fully implemented • Correct wrong number entries by swiping across the display • Cut/copy/paste of display value • Double-tap display to view the stack and memory registers • Visual indicators keep track of input parameters entered • 10 non-volatile memory registers (not available in original HP-70) The HP-70 was discontinued after just one year. It is one of the rarest calculators, hard to find in any condition. NOTE: RPN-70 SD is a faithful simulation of a vintage HP-70 calculator, as has been verified against a real device using the examples in the Applications Cookbook section of the HP-70 manual. In certain cases, what may appear like a bug of the app is actually an idiosyncrasy of the HP-70. IMPORTANT: The HP-70 requires exactly three input parameters from the top-row keys, at least one of them being either "n" or "i". In other words, you can't use PMT, PV, and FV as input parameters simultaneously. A version for the iPhone named "RPN-70 HD" is also available. Short manual and sample calculations on the website: www.cuveesoft.ch
Stack RPN Calculator
This scientific calculator displays major functions on screen and utilizes a stack for calculations. It supports a stack of up to 4 values but can store many more numbers depending on device memory.
- Visible scientific functions
- RPN (Reverse Polish Notation) input
- Stack display for up to 4 values
- Large number storage capacity
- Designed for iPhone and iPad
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RPN scientific calculator benefiting from the major scientific functions visible on the screen. The calculator shows a stack of up to 4 values but can store a large number of numbers (depends on the phone's memory).
Screenshots
Verdict
The clearest difference is review sentiment: RPN at 100% against Stack RPN Calculator's 33%. RPN also leads on rating (4.7 vs 3.5) and ratings volume (11 vs 2). On price, ads, in-app purchases and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
RPN holds the better App Store score, 4.7 against 3.5. That said, the two scores are not equally well evidenced: RPN has 11 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 100% of RPN's written reviews are positive against 33% of Stack RPN Calculator's.
| Parameter | RPN | Stack RPN Calculator |
|---|---|---|
| Price | Free | Free |
| Rating | 4.7 (11 ratings) — better | 3.5 (2 ratings) |
| Positive reviews | 100.0% of reviews — better | 33.3% of reviews |
| Number of ratings | 11 — better | 2 |
| Update frequency | Every 7 months | — |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 12.0 | 11.0 — better |
| Further details — not scored | ||
| Size | 17 MB | 10 MB |
| Age rating | 4+ | 4+ |
| Developer | CuVee Software | Dario Bersiga |
Customer experience
RPN
Stack RPN Calculator
In-app purchases
RPN
No in-app purchases
Stack RPN Calculator
No in-app purchases






