RPNPro vs RPNu
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
RPNPro
This calculator utilizes Reverse Polish Notation (RPN) for input, mirroring the functionality of classic HP calculators. It features a four-level stack with X, Y, Z, and T registers, displaying the X register in decimal, hexadecimal, and binary.
- Reverse Polish Notation (RPN) input
- Four-level stack (X, Y, Z, T registers)
- Decimal, hexadecimal, and binary display
- Modeled after HP calculators
- Designed for software engineers
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RPNPro is a calculator for software engineers. RPNPro uses RPN (Reverse Polish Notation) as an input scheme. It is based on the same four level stack model as provided by the original HP (Hewlett-Packard) calculators, featuring X, Y, Z and T registers. The contents of the X register are always shown in decimal, hexadecimal and binary notation.
RPNu
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RPNu is a calculator that makes crunching numbers easier than it’s algebraic equivalent. RPN stand for Reverse Polish Notation (The ‘u’ stands for universal, meaning it runs on both the iPad and iPhone.) and is the numeric evaluation method used for this app. RPN, I feel, is far superior to the algebraic method and once learned you will never want to use the algebraic again. This calculator has all the normal mathematical function, but also contains a host of other functions that you may find very useful. Space is limited in this description but here are the highlights: Help: There is extensive help to aid the user in determining how to use this app. It is also context sensitive. Programable: You can write your own programs and there are many tools to aid you in doing this. Graphics: You can graph equations and there are several modes to cover almost all requirements. A universal converter that you will find very useful. Matrix arithmetic (determinate, invert, add, subtract and multiply). Date calculator and an hours calculator with moon phase display. Elements and periodic table information. Combinations and permutations calculator Equation integration and root finder. Amortization with many useful functions. Mapping function that allows you to determine distance between points and other functions. Hyperbolic functions. Hexadecimal, Octal, and Binary modes. Barometer function showing QNE and QNH. A compass that not only shows magnetic and true north, but also shows the address you are at. This app includes extensive support for a Bluetooth keyboard. Also, extensive support is given to export your calculations to either email or the universal clipboard.
Screenshots
Verdict
The clearest difference is update cadence: RPNu at every 2 months against RPNPro's every 37 months. RPNPro's advantage is iOS requirement (9.1 vs 15.0). On price, ads, in-app purchases 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. Neither carries in-app purchases, so what you see is what you pay.
RPNPro ships an update every 37 months, RPNu every 2 months. The most recent releases landed on October 14, 2026 and October 26, 2026 respectively.
| Parameter | RPNPro | RPNu |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | — |
| Positive reviews | 50.0% of reviews | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 37 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 9.1 — better | 15.0 |
| Further details — not scored | ||
| Size | 1 MB | 49 MB |
| Age rating | 4+ | 4+ |
| Developer | Felix Meier | Scott Johnson |
In-app purchases
RPNPro
No in-app purchases
RPNu
No in-app purchases









