# Three (Rule of 3 Calculator) — Simple everyday-use calculator

> Simple calculator for everyday proportional calculations and conversions. (iPhone/iPad app by Pericles Maravelakis.)

- Source: https://appshunter.io/ios/app/three-rule-of-3-calculator/id683066955 (this page in markdown: same URL + `.md`)
- Developer: [Pericles Maravelakis](https://appshunter.io/developer/392585599)
- Category: Utilities, Education
- Price: Free
- Rating: 5.00/5 from 2 App Store ratings
- Age rating: 4+
- Requires: iOS 15.0 · 1 MB
- Languages: American English
- Released: 2014-01-30
- Data updated: 2026-06-06
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/three-rule-of-3-calculator/id683066955/reviews.md

## What is Three (Rule of 3 Calculator)?

For example:
If my car consumes an average 8.8 litres of gas per 100 kilometers, a 350 kilometer trip will consume 30.8 litres (and therefore $61.6 if gas price is $2/litre)...

...or a fast currency converter: if 1 Euro is about 1.09 US dollars, 33.9 EUR is 36,92 USD.

Three can also be used for measurements, image sizes, grocery shopping and more.
As simple and trivial it is, the rule is used daily in practical arithmetics.

The application has a simple and modern interface to perform fast calculations and includes some basic options to facilitate the displaying results (thousands separator, decimal digits) including color customization in dark/light modes.

## Key features

- Rule of 3 calculations
- Currency conversion
- Measurement conversions
- Grocery shopping calculations
- Simple and modern interface
- Result display customization
- Dark/light mode support


## Frequently asked questions about Three (Rule of 3 Calculator)

### What is Three (Rule of 3 Calculator) used for?

Three (Rule of 3 Calculator) is designed for performing quick, everyday proportional calculations. This includes tasks like calculating fuel consumption for a trip, converting currencies, or estimating grocery needs.

### Does Three (Rule of 3 Calculator) have ads?

No, Three (Rule of 3 Calculator) is ad-free. The application does not contain any advertisements, providing an uninterrupted user experience.

### What devices is Three (Rule of 3 Calculator) available on?

Three (Rule of 3 Calculator) is available on iPhone, iPad, and iPod. It is designed to work across these Apple devices.

### How often is Three (Rule of 3 Calculator) updated?

The latest version of Three (Rule of 3 Calculator) is 3.2.0, which was last updated on September 21, 2023. Updates are released periodically to improve functionality and compatibility.

### What is the age rating for Three (Rule of 3 Calculator)?

Three (Rule of 3 Calculator) has an age rating of 4+. This indicates it is suitable for users aged four and older.

### Can I customize the display of results in Three (Rule of 3 Calculator)?

Yes, the application includes basic options to facilitate the displaying of results. You can customize features like the thousands separator and the number of decimal digits.

### What is the user feedback on Three (Rule of 3 Calculator)?

Based on the available data, Three (Rule of 3 Calculator) has received a perfect 5.0-star rating from 2 reviews, indicating very positive user sentiment.

### Is Three (Rule of 3 Calculator) free to download?

Yes, Three (Rule of 3 Calculator) is completely free to download and use. There are no costs associated with acquiring or operating the application.

## Version history (last 5 releases)

### 3.2.0 — 2023-09-21

iOS 17 support plus some minor fixes and improvements.

### 3.0.0 — 2023-06-26

After a long hiatus, the app was written from scratch including full support for iOS 15 and 16.

### 2.1.1 — 2018-01-15

- iOS 11 and iPhone X compatibility.
- New Dark Mode Interface.
- Customise the interface with the color you like.

### 2.1.0 — 2018-01-02

- iOS 11 and iPhone X compatibility.
- New Dark Mode Interface.
- Customise the interface with the color you like.

### 2.0 — 2017-01-08

Version 2.0 brings a complete interface redesign for all iOS devices, with live result preview as you type and removal of all advertisements.

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## More apps by Pericles Maravelakis

- [Homer Works (Ομήρου Έπη)](https://appshunter.io/ios/app/homer-works/id392585596)
- [Radiofonic: Music & Live News](https://appshunter.io/ios/app/radiofonic-music-and-live-news/id633917968)

All apps by Pericles Maravelakis: https://appshunter.io/developer/392585599

## Related topics

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

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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 2026-06-06.*