Calculate side lengths, angles, area, and perimeter of right-angle triangles. Visualizes the triangle with adjustable precision and offers options to rotate, flip, and customize themes. Reuses previous entries for efficiency.






250+ iOS apps curated and reviewed
Triangle Calculator is the household name in diagonal calculator, but it's far from the only option. We track 250+ alternatives and competitors on iOS — many free, many higher-rated than you'd expect.
| # | App | Price | Rating | Ads | In-App Purchases | Updated |
|---|---|---|---|---|---|---|
| 1 | Free | 5.0★ (2) | No | No | May 2026 | |
| 2 | Free | 4.7★ (140) | Yes | No | Aug 2026 | |
| 3 | Free | 4.6★ (401) | Yes | Yes | Aug 2026 | |
| 4 | Free | 4.5★ (905) | No | Yes | Aug 2026 | |
| 5 | Free | 4.8★ (21K) | Yes | No | Aug 2026 | |
| 6 | $5.99 | 4.7★ (6.3K) | No | Yes | Aug 2026 | |
| 7 | Free | 4.6★ (242) | No | Yes | Aug 2026 | |
| 8 | Free | — | No | Yes | Aug 2026 |






Calculate side lengths, angles, area, and perimeter of right-angle triangles. Visualizes the triangle with adjustable precision and offers options to rotate, flip, and customize themes. Reuses previous entries for efficiency.






Easily calculate lengths, angles, and areas of various geometric shapes. Input known values and instantly get precise results for a wide range of 2D and 3D figures. Ideal for students and engineers needing quick geometric computations.






A powerful construction calculator designed for tradespeople. It offers a wide range of tools for estimating, layout, framing, and jobsite calculations, helping to save time and improve accuracy. Supports both imperial and metric units.


This app simplifies complex calculations for construction professionals. It offers a variety of tools for tasks like spacing, measurements, and material estimation, helping to reduce errors and save time on job sites. Available on iPhone and iPad, it aims to be an essential tool for tradespeople.


This app provides 15 calculators for estimating concrete, blocks, mortar, rebar, and gravel. It supports various shapes and units, offering material cost estimations for construction projects.


This advanced calculator app offers a powerful math core and algebra engine for basic to complex calculations. It includes features like step-by-step solutions, handwriting recognition, and 2D graphing, making it suitable for students, engineers, and programmers.


Easily calculate any side of a right-angled triangle using the Pythagorean theorem. Input two sides to find the third, with all calculations saved in a history. Supports fractions and offers an ad-free option.
















A fast, clean, and easy-to-use calculator app offering both basic and advanced scientific functions. It features a minimal design, calculation history, and supports dark and light modes for a comfortable daily calculation experience.






This utility app performs complex construction calculations using feet and inches, down to the sixteenth. It offers tools for layout diagonals, gable and jack rafters, and roof decking for hip roofs.


This is a simple and aesthetically pleasing calculator app designed for iPhone. It offers essential arithmetic functions with a calming pink interface and user-friendly features like haptic feedback and calculation history. It operates completely offline and is free to use.


This app offers a user-friendly calculator with large buttons and extensive customization options. It features a dual-line display to see input and results simultaneously, saves your calculation history, and provides full scientific functions. Personalize layouts, themes, and even button symbols to suit your needs.