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.






220+ iOS apps curated and reviewed
Triangle Calculator is the household name in diagonal calculator, but it's far from the only option. We track 220+ 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★ (134) | Yes | No | Aug 2026 | |
| 3 | Free | 4.6★ (401) | Yes | Yes | Aug 2026 | |
| 4 | Free | 4.5★ (903) | No | Yes | Aug 2026 | |
| 5 | Free | 4.8★ (39K) | No | Yes | Aug 2026 | |
| 6 | Free | 4.8★ (21K) | Yes | No | Aug 2026 | |
| 7 | Free | 4.8★ (13K) | No | Yes | Aug 2026 | |
| 8 | Free | 4.6★ (242) | 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 is a powerful construction calculator designed for professionals working with dimensions. It offers a wide range of solutions for dimensional math, right angle calculations, area and volume, and special functions, helping to improve speed and accuracy in layouts, bids, and estimates.


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 app is a powerful feet-inch-fraction calculator designed for construction professionals. It offers advanced calculation capabilities for layouts, bids, and estimates, simplifying complex measurements and conversions for enhanced project accuracy and efficiency.


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.


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 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.


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.


This app accurately calculates the weight, length, and cost of various metals and liquids. It supports a wide range of materials and shapes, offering multiple unit options for precise measurements and financial planning.


This free calculator app offers a fast, ad-free experience with a visual input and calculation history. Customize your experience with various keyboard sounds and colors, and access advanced scientific functions when needed.


This app offers a comprehensive suite of over 40 calculators and unit converters for various needs, including finance, health, construction, and everyday math. It features standard, scientific, and specialized calculators for tasks like loan amortization, currency conversion, and material estimation.


Easily perform fraction calculations including addition, subtraction, multiplication, and division. Convert fractions to decimals and vice versa with a clear, user-friendly interface. Ideal for students, cooks, and DIYers needing quick and accurate fraction management.


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 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 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 provides specialized calculators for construction professionals, including concrete, rebar, and area/volume calculations. It offers material quantity estimation, unit conversion, and professional features like BOQ export and project organization. Designed for contractors, builders, and engineers on job sites worldwide.


This app offers a versatile calculator with multiple modes, including scientific, bitwise, statistical, trigonometric, base conversion, and time calculations. It features a simple mode with large buttons and customizable interface. Widgets for notification center and Apple Watch are also included.