CMCalc vs RPNu
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
CMCalc
This app emulates a classic 1980s computer math calculator, offering decimal arithmetic, binary conversions, and logic functions. It supports parentheses for complex calculations and includes modern features like copy/paste and landscape mode.
- Decimal arithmetic
- Binary conversions (decimal, binary, octal, hexadecimal)
- Binary logic functions
- Operator grouping with parentheses
- Hexadecimal input (A-F)
- Copy and paste results/functions
- Landscape mode
Read full descriptionHide full description
The CMCalc application is a replica of the Casio CM-100 Computer Math Calc solar powered calculator that was sold in the mid 1980’s. It performs simple decimal arithmetic and basic binary conversions (decimal - binary - octal - hexadecimal) and binary logic functions. While it is a standard infix calculator, it supports operator grouping with parentheses. For hexadecimal calculations, the input keys include A through F. CMCalc application performs all the same functions as the calculator, and has the same look as the original. There are a couple features that were not conceivable in the 1980’s on a calculator … such as the ability to copy and paste the results or the entered function, and a landscape mode for devices with 4 inch or larger screens. The face of the calculator can be viewed in two modes including a traditional application style, and a photo replica of the original calculator face.
RPNu
Read full descriptionHide full description
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 CMCalc's every 45 months. CMCalc's advantage is iOS requirement (12.0 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.
CMCalc ships an update every 45 months, RPNu every 2 months. The most recent releases landed on October 24, 2026 and October 12, 2026 respectively.
| Parameter | CMCalc | RPNu |
|---|---|---|
| Price | Free | Free |
| Rating | 4.6 (7 ratings) — better | — |
| Positive reviews | 75.0% of reviews | — |
| Number of ratings | 7 — better | — |
| Update frequency | Every 45 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 12.0 — better | 15.0 |
| Further details — not scored | ||
| Size | 4 MB | 49 MB |
| Age rating | 4+ | 4+ |
| Developer | William David | Scott Johnson |
In-app purchases
CMCalc
No in-app purchases
RPNu
No in-app purchases









