Kalkulators vs RPNu
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Kalkulators
This app allows for complex calculations using numbers, operators, and variables. It offers multiple calculator instances and theme customization. Advanced mathematical functions and extended limits are available via in-app purchase.
- Expression input with operators and parentheses
- Real-time calculation as you type
- Variable support for dynamic calculations
- Multiple calculator instances
- Customizable themes (light/dark)
- User-defined precision
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Kalkulators = expression calculators. Examples: 1 + 2 + (5 - 2.345) 22.0 / 7 * (a +b) Features: - Expression: use numbers, parenthesis, operators: + - * / - No need for an "=" button. Calculates as you type. - Mathematical functions (with inApp purchase) - Variables: use them in the expression. Useful for example, to change the values without editing the expression - iPhone: "Basic" mode for quick calculations (no variables) - Multiple Kalkulators - Duplicate Kalkulator: easily compare results by using different values in an expression/variables - Preferences: theme (light/dark), precision, thousands separator With Kalkulators you will never need to write down those intermediate results. Buy the Pro version from the in-App store to unlock it's full potential. Buy it once and unlock both the iPad and iPhone Pro features. Note that Kalkulators is an iPad and iPhone app. Here are the differences • iPad: - Albums: let's you organize your formulas (maximum 5) - Formulas: let's you store your formulas (maximum 3/album) - Kalkulators: open many kalkulators at the same time (maximum 2) - Kalkulators variables: reference them in your formulas for quicker, more convenient calculations (2 variables) • iPhone: - Formulas: let's you store your formulas (maximum 2) - Kalkulators variables: reference them in your formulas for quicker, more convenient calculations (1 variable) • iPad and iPhone: - Duplicate Kalkulators - Two themes: light and dark - User defined precision (decimals) With the in-App purchase, this is what you get: • iPad: - Albums: maximum 100 - Formulas: maximum 100/album, no limit on the expression length - Kalkulators: maximum 20 - Kalkulators variables: 10 variables - Scientific keyboard with trigonometric and math functions • iPhone: - Formulas: maximum 100, no limit on the expression length - Kalkulators variables: 3 variables - Scientific keyboard with trigonometric and math functions
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 in-app purchases: RPNu at none against Kalkulators's 1. RPNu also leads on update cadence (every 2 months vs every 9 months). On price, ads, device support and iOS requirement 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. Kalkulators sells 1 one-off in-app purchase. RPNu asks for nothing beyond the download.
Kalkulators ships an update every 9 months, RPNu every 2 months. The most recent releases landed on October 8, 2026 and October 12, 2026 respectively.
| Parameter | Kalkulators | RPNu |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 9 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 15.0 |
| Further details — not scored | ||
| Size | 21 MB | 49 MB |
| Age rating | 4+ | 4+ |
| Developer | iPinsoft | Scott Johnson |
In-app purchases
Kalkulators
- Kalkulators Pro$0.99
RPNu
No in-app purchases









