Open Source Android Scientific Calculators

Advanced Trigonometry Calculator (ATC) is an open-source mathematical computing engine written mainly in C/C++. Created in 2011 and maintained by Renato Alexandre dos Santos Freitas, ATC is designed as a practical Windows desktop application for advanced calculations, automation, and technical problem solving. ATC supports equation solving, polynomial tools, complex numbers, matrix calculations, statistics, physics, geometry, unit conversions, DSP/FFT operations, and scripting. It can also process batch TXT files, making it useful for repeatable calculations and automated workflows. The project also includes ATC Online Alpha, a WebAssembly-based version that brings parts of the ATC engine to the web. ATC is released under the GPLv3 license and is made in Portugal.

PeCalc allows making calculations with integer fractions, complex numbers, complex matrices, rational functions and complex polynomials. It also allows making changes of numeric base, prime factor decomposition, solving linear equation systems, statistical and financial computations, rational fraction decomposition and plotting some control engineering graphs. PeCalc includes comprehensive user help in English and Spanish. Currently PeCalc runs on Android and MS Windows. A version for GNU Linux is planned for the near future. It has been developed in Object Pascal using Embarcadero Delphi. A Lazarus/Free Pascal version will be available soon too.