RPNPro vs Dozecal
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.
Dozecal
This educational calculator promotes the use of Base Twelve (duodecimal) in math and science. It offers standard mathematical functions in both duodecimal and decimal modes, with automatic conversion between them. It utilizes Reverse Polish Notation (RPN) for calculations.
- Duodecimal and Decimal modes
- Automatic mode conversion
- RPN (Reverse Polish Notation) input
- Standard math functions
- Trigonometric operations (degrees)
- Educational tool for Base Twelve
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Dozecal is an educational RPN* calculator to promote the use of Base Twelve in math and science. The usual math functions are available in both DUODECIMAL and DECIMAL modes. Conversion is automatically made when switching from one mode to the other one. Trigonometric operations uses DEGREE as unit of measure. For more information about Base 12, please visit the Dozenal Society of America. * RPN : the Dozecalc calculator uses the Reverse Polish Notation (RPN). This notation seems complex but has many advantages over algebraic notation and is more intuitive once you have understood the idea. The calculator has a stack and any operation that requires two numbers is using the bottom stack layers (X and Y). Key ENTER to push the stack up and separate one number from the next. To perform arithmetic, key in the first number, press ENTER to separate the first number from the second, then key in the second number and then select and operator such as the numerical functions +, -, * or /. The result appears immediately after you press the numerical function key. The operator is keyed in only after both operands are in the stack. Example: calculate 3 + 4 Key sequence: 3 ENTER 4 + Result: 7 The result of any operation may itself become an operand. You do not need to press enter again to use the result. The "7" is already entered. Example: add 2 to the previous result Key sequence: 2 + Result: 9 Example: calculate 5 * (3 + 4) Key sequence: 3 ENTER 4 + 5 * Alternate key sequence: 5 ENTER 3 ENTER 4 + * Disclaimer: results and precision may occasionally be incorrect. Should you report them at johan@unumdesignum.com, and the author will be happy to fix !
Screenshots
Verdict
The clearest difference is rating: RPNPro at 5.0 against Dozecal's 4.0. RPNPro also leads on iOS requirement (9.1 vs 12.0). Dozecal's advantage is review sentiment (75% vs 50%) and update cadence (every 10 months vs every 37 months). 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.
RPNPro holds the better App Store score, 5.0 against 4.0. Both are backed by a comparable volume of ratings — 1 and 4 respectively. Written reviews complicate that: 50% of RPNPro's written reviews are positive against 75% of Dozecal's, so the app with the better star average is not the one people write more warmly about.
RPNPro ships an update every 37 months, Dozecal every 10 months. The most recent releases landed on September 28, 2026 and October 2, 2026 respectively.
| Parameter | RPNPro | Dozecal |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | 4.0 (4 ratings) |
| Positive reviews | 50.0% of reviews | 75.0% of reviews — better |
| Number of ratings | 1 | 4 — better |
| Update frequency | Every 37 months | Every 10 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 9.1 — better | 12.0 |
| Further details — not scored | ||
| Size | 1 MB | 27 MB |
| Age rating | 4+ | 4+ |
| Developer | Felix Meier | Johan Kovacs |
Customer experience
RPNPro
Dozecal
In-app purchases
RPNPro
No in-app purchases
Dozecal
No in-app purchases









