Stackis RPN vs RPN
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Stackis RPN
A calculator designed for users who prefer Reverse Polish Notation (RPN). It offers a familiar interface for RPN users and includes support for duodecimal calculations.
- RPN calculation style
- Duodecimal (dozenal) support
- Familiar interface for RPN users
- Simple and pleasant user experience
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This is an RPN calculator in the style of, for instance, old HP models. It will feel familiar if you are used to RPN, otherwise it will probably be a little confusing at first. It's not programmable and it doesn't try to mimic older hardware; it's just meant to be a pleasant calculator for those who prefer to use RPN. Also, if you want to perform calculations in duodecimal (dozenal), this app is for you!
RPN
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This is a calculator app using Reversed Polish Notation (RPN) In Portrait mode, this app provides a basic calculator with the four arithmetic disciplines +, -, x, and /. In Landscape mode, 30 extra buttons are available providing most functions found on a scientific calculator. You can do trigonometry, logarithms, roots, probability, and more. RPN is neat because you can do fancy calculations without having to worry about parenthesis. Putting the operator after the operands allow the operator to infer which are its operands without the clarification offered by paranthesis. The built-in help function (?) provides a short description of each function. The settings page allows you to set the number format, number of decimals displayed, decimal separator and more.
Screenshots
Verdict
The clearest difference is in-app purchases: RPN at none against Stackis RPN's 1. RPN also leads on iOS requirement (15.6 vs 17.6). Stackis RPN's advantage is update cadence (every 4 days vs every 6 months). On price, ads and device support 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. Stackis RPN sells 1 one-off in-app purchase. RPN asks for nothing beyond the download.
Stackis RPN ships an update every 4 days, RPN every 6 months. Both last shipped on October 12, 2026.
| Parameter | Stackis RPN | RPN |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (2 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 2 — better | — |
| Update frequency | Every 4 days — better | Every 6 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free | — |
| Devices | iPhone, iPod | iPhone, iPod |
| Requires iOS | 17.6 | 15.6 — better |
| Further details — not scored | ||
| Size | 10 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | Skimra | Joachim Seland Graff |
In-app purchases
Stackis RPN
- Advanced Mode$1.99
RPN
No in-app purchases
