# Rule of Three Calculator Pro — Mathematics rule of three

> App for calculating proportional and anti-proportional values using the rule of three. (iPhone/iPad app by Gustav Gutsche.)

- Source: https://appshunter.io/ios/app/rule-of-three-calculator-pro/id6447561990 (this page in markdown: same URL + `.md`)
- Developer: [Gustav Gutsche](https://appshunter.io/developer/1661525357)
- Category: Education, Productivity
- Price: $1.99
- Age rating: 4+
- Requires: iOS 16.0 · 4 MB
- Languages: American English, German (Germany)
- Released: 2023-04-11
- Data updated: 2026-08-21
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/rule-of-three-calculator-pro/id6447561990/reviews.md

## What is Rule of Three Calculator Pro?

Rule of Three Calculator - The key to mathematics!

Imagine an app that simplifies the tedious process of calculating proportional and anti-proportional values. 
Our "rule of three calculator" is exactly what you need!

Features:

- Easy input: enter your values in the a, b and y fields and let the app do the rest!
- Choose your calculation type: decide if your ratio is proportional or anti-proportional and see the underlying formula right on the screen.
- Immediate results: Get instant clarity with clear and precise results, displayed in the 'x' field.
- Intuitive user interface: a clean and modern design suitable for both beginners and advanced users.
- Multilingual support: whether you speak English or German, our calculator is ready to serve you in your language.

Download the rule of three calculator now and make your calculating work easier!

## Key features

- Easy input of values
- Proportional and anti-proportional calculation types
- Immediate and precise results
- Intuitive user interface
- Multilingual support

## Recent user reviews (1 of 1)

All indexed reviews: https://appshunter.io/ios/app/rule-of-three-calculator-pro/id6447561990/reviews.md

### 3/5 — Ganz nett

*2026-03-26*

Dafür, dass er was kostet eher bescheiden. Negative Werte gehen garnicht, keine Möglichkeit eine Eingabe mit einem ‘Click’ zu löschen.

## Frequently asked questions about Rule of Three Calculator Pro

### What is the Rule of Three Calculator Pro?

Rule of Three Calculator Pro is a paid application designed to simplify the calculation of proportional and anti-proportional values. It allows users to input values and select calculation types for immediate results.

### How do I use the Rule of Three Calculator Pro?

You enter your known values into the 'a', 'b', and 'y' fields. Then, you choose whether your ratio is proportional or anti-proportional. The app will then display the calculated 'x' value.

### What devices does the Rule of Three Calculator Pro support?

The Rule of Three Calculator Pro is available for iPhone and iPad devices.

### Is the Rule of Three Calculator Pro suitable for beginners?

Yes, the app features an intuitive user interface with a clean and modern design, making it suitable for both beginners and advanced users.

### Does the Rule of Three Calculator Pro offer multilingual support?

Yes, the calculator is available in multiple languages, including English and German, to serve a wider user base.

### How often is the Rule of Three Calculator Pro updated?

The app was last updated on January 10, 2025, with version 2024.10. This indicates regular maintenance and potential feature additions.

### What is the age rating for the Rule of Three Calculator Pro?

The app has an age rating of 4+, making it appropriate for a wide range of users, including younger students.

### Does the Rule of Three Calculator Pro have ads?

No, the Rule of Three Calculator Pro does not contain advertisements. It is a paid application without any in-app purchases or ads.

## Version history (last 3 releases)

### 2024.10 — 2025-01-10

We've made some general improvements & fixed some bugs.

### 2023.276 — 2023-10-05

- New user interface
- Numbers in US format
- Proportional and antiproportional calculations
- Calculation formula is now displayed

### 1.0 — 2023-04-11

No release notes.

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## More apps by Gustav Gutsche

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All apps by Gustav Gutsche: https://appshunter.io/developer/1661525357

## Related topics

[rule of three calculator pro](https://appshunter.io/ios/topics/rule-of-three-calculator-pro)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-21.*