Open Source C Scientific Calculators

This project has created scientific firmware for the HP-20b and HP-30b business calculators. WP 34S turns either of these calculators into a powerful keystroke programmable scientific device. According to our customers, it's the most powerful and fastest RPN scientific pocket calculator ever built. WP 34S is alive and stable since 2011. We have succeeded in satisfying the most picky users - read about their experiences on http://www.hpmuseum.org/forum/forum-8.html. Since 2014, WP 34S runs in version 3.3. Our customers confirm its documentation is excellent and comprehensive (see feedback); a full-color printed edition is available from https://www.amazon.com/dp/153366238X since 2018-10-15. Alternatively, you can get a personalized pdf-manual for a ≥ 9 US$ donation here. We have also produced the WP 31S which is derived from the WP 34S source code. This is an entry-level scientific calculator. Its printed manual is available from https://www.amazon.com/dp/1499231164 .

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.

Wcalc is a powerful arbitrary-precision calculator. It has standard functions (sin, asinh, logtwo, floor, etc), many pre-defined constants (pi, e, c, etc.), variables, "active" variables, command history, and hex/octal/binary i/o, conversions, and more

Mole (Chemistry Calculator) can calculate molar mass, number of moles and atoms, empirical and molar formulas and can do stoichiometric calculations such as percent yield and limiting reactant. Mole can also do gas stoichiometry and gas law calculations.

Engineering Calculator Suite

A simple scientific calculator for complex number calculation. It requires the GTK+ toolkit.