243+ iOS apps curated and reviewed
From beginner-friendly picks to power-user tools, our rule of three calculator pro list covers 243+ iPhone apps updated through August 2026. Compare ratings, prices, and screenshots in one place.
| # | App | Price | Rating | Ads | In-App Purchases | Updated |
|---|---|---|---|---|---|---|
| 1 |  | $1.99 | — | No | No | Jun 2026 |
| 2 |  | Free | 4.9★ (409K) | Yes | No | Sep 2026 |
| 3 |  | Free | 4.7★ (61K) | No | No | Sep 2026 |
| 4 |  | Free | 4.8★ (20) | No | Yes | Aug 2026 |
| 5 |  | Free | 5.0★ (4) | Yes | No | Jul 2026 |
| 6 |  | Free | — | No | Yes | Aug 2026 |
| 7 |  | Free | 5.0★ (2) | No | No | May 2026 |
| 8 |  | Free | 4.9★ (34K) | Yes | Yes | Sep 2026 |
This app simplifies calculations involving proportional and anti-proportional values. Easily input your numbers and select the calculation type to get immediate, precise results. Its intuitive interface and multilingual support make it accessible for all users.
This utility app offers a clean and intuitive interface for performing calculations. It prioritizes a user-friendly design with large buttons and a clear display for quick and efficient use.
This app offers both basic and scientific calculation modes with over 30 scientific operations. It allows for customization of the app's appearance and includes features for note-taking, drawing, and viewing calculation history. It supports high accuracy calculations and nested parentheses.
This app simplifies product multiplication calculations with a quick ratio calculator. Easily copy results to your clipboard or save them for future reference in your history with a premium account.
Easily solve proportion problems with a simple and intuitive interface. This app uses the cross product method for quick and accurate calculations across various fields like finance and science. It's available offline and free to use.
This utility app simplifies calculations for the Rule of Three, supporting both direct and indirect proportion modes. It is designed with accessibility in mind, optimized for VoiceOver and other assistive features.
This utility app helps users perform quick calculations for everyday scenarios like fuel consumption, currency conversion, and grocery shopping. It features a simple interface with options for result display customization and supports dark/light modes.
This app offers a straightforward calculation experience, focusing on essential functions without unnecessary complexity. It includes basic arithmetic, percentage calculations, and advanced functions like square root. Users can customize the appearance with multiple color schemes and utilize features like result copying and split-screen multitasking on iPad.
This app offers a free basic and scientific calculator with an intuitive interface. It supports fractions, percentages, and advanced editing. Optional upgrades provide specialized calculators for fractions with units, polynomial and linear equation solving, graphing, and geometric shapes.
This multi-function calculator offers basic to advanced scientific and algebraic computations. It includes features like handwriting recognition, equation solvers, and 2D graphing, making it suitable for students and professionals. In-app purchases unlock advanced capabilities.
A straightforward and reliable calculator application designed for iPad and iOS 9. It offers a standard calculation experience with a charming piano sound effect and is optimized for high-resolution screens.
This app offers both basic and advanced scientific calculations with an intuitive interface designed for tablets and phones. It includes features like currency conversion, calculation history, and the ability to share results. An optional premium membership removes ads and provides enhanced support.
This utility app offers a straightforward calculation experience with a vast selection of over 80 customizable themes. Personalize your calculator's appearance to suit your style while performing everyday math tasks.
Perform essential arithmetic operations with a straightforward calculator app. Its large buttons and clear display ensure ease of use, supporting both portrait and landscape orientations.
A free, classic calculator app with large, easy-to-press buttons and customizable skins. It supports basic arithmetic, memory functions, and can handle very large numbers without using scientific notation. Multitasking is also supported on compatible devices.
This utility app simplifies calculations using the rule of three. It offers a straightforward interface for solving proportion problems, making it easy to find unknown values. The app is completely free and ad-free.
This utility app helps you solve problems involving ratios and proportions. It calculates an unknown number based on the relationship between two other known numbers.
This app offers a clean and intuitive interface for both basic arithmetic and advanced scientific calculations. It includes a history tape to review past computations and supports various mathematical operations, making it suitable for everyday use and complex problem-solving.
This app redefines the calculator experience for touch-screen devices with a modern, intuitive design. It offers features like a tape log for storing calculations, formula evaluation, and iPad multitasking support for enhanced productivity.