Browse free open source C Calculators and projects below. Use the toggles on the left to filter open source C Calculators by OS, license, language, programming language, and project status.

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  • 1

    TILP - TI Linking Program

    TI graphing calculators <-> computer communication software

    TILP (formerly GtkTiLink) can transfer data between Texas Instruments graphing calculators and a computer. It works with all link cables (parallel, serial, Black/Gray/Silver/Direct Link) and it supports the TI-Z80 series (73..86), the TI-eZ80 series (83PCE, 84+CE), the TI-68k series (89, 92, 92+, V200, 89T) and the Nspire series (Nspire Clickpad / Touchpad / CX, both CAS and non-CAS). The project is now managed on Github, https://github.com/debrouxl/tilp_and_gfm . It uses the libti* libraries, https://github.com/debrouxl/tilibs . Install script for *nix: https://github.com/debrouxl/tilp_and_gfm/blob/master/tilp/trunk/build/scripts/install_tilp.sh
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    Downloads: 487 This Week
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  • 2
    CRC RevEng

    CRC RevEng

    Arbitrary-precision CRC calculator and algorithm finder

    CRC RevEng is a portable, arbitrary-precision CRC calculator and algorithm finder. It calculates CRCs using any of the 113 preset algorithms, or a user-specified algorithm to any width. It calculates reversed CRCs to give the bit pattern that produces a desired forward CRC. CRC RevEng also reverse-engineers any CRC algorithm from sufficient correctly formatted message-CRC pairs and optional known parameters. It comprises powerful input interpretation options. Compliant with Ross Williams' Rocksoft(tm) model of parametrised CRC algorithms.
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    Downloads: 287 This Week
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  • 3
    Open Tax Solver

    Open Tax Solver

    Calculates income tax form entries, helps do your taxes.

    OTS is a safe, secure, easy-to-use program for calculating Tax Return Form entries, and determining your tax-owed or refund-due, for Federal or State personal income taxes. Includes updated versions for US 1040, Schedules A, B, C, D, and for several states. OTS provides both graphical and textual interfaces for quickly filing out your tax forms. --- Best way to download the correct version for your platform -- go to the OTS WEBSITE: =====> https://opentaxsolver.sourceforge.net/
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    Downloads: 112 This Week
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  • 4
    Osmo
    Osmo is a handy personal organizer, which includes calendar, tasks manager, address book and notes modules. It was designed to be a small, easy to use and good looking PIM tool to help to manage personal information.
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    Downloads: 51 This Week
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  • 5
    WP 34s

    WP 34s

    Scientific/engineering firmware repurposing HP business 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 .
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    Downloads: 45 This Week
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  • 6
    This emulator is capable of providing a faithful replication of the HP48. It also has a debugger for the saturn processor.
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    Downloads: 46 This Week
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  • 7
    4tH compiler

    4tH compiler

    A friendly Forth compiler with a little difference

    4tH is a Forth compiler with a little difference. Instead of the standard Forth engine it features a conventional compiler. 4tH is a very small compiler that can create bytecode, C-embeddable bytecode, standalone executables, but also works fine as a scripting language. It supports about 95% of the ANS Forth CORE wordset and features conditional compilation, pipes, files, assertions, forward declarations, enumerations, structures, suspended execution, recursion, include files, etc. It comes with an RPN calculator, BASIC interpreter, line editor, preprocessor, compiler, decompiler, C-source generator, a virtual machine, and a multitasking environment.
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    Downloads: 55 This Week
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  • 8
    Advanced Trigonometry Calculator

    Advanced Trigonometry Calculator

    Open-source C/C++ math engine for advanced scientific computing

    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.
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    Downloads: 18 This Week
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  • 9

    calc: C-style arbitrary precision system

    Calc: arbitrary precision C-like arithmetic & calculator

    Calc is arbitrary precision C-like arithmetic system that is a calculator, an algorithm prototyper and mathematical research tool. Calc comes with a rich set of builtin mathematical and programmatic functions.
    Downloads: 11 This Week
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  • 10
    'atlc' is a CAD package used for analysing and desiging electrical transmission lines of arbitrary cross section. Also for the design of directonal couplers. Some parts are CPU intensive, so multiple CPUs are supported.
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    Downloads: 12 This Week
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  • 11
    Scientific calculator for PalmOS and PocketPC with graphing, financial operations, number conversions, complex numbers and much more.
    Downloads: 8 This Week
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  • 12
    Wcalc

    Wcalc

    A powerful arbitrary-precision calculator.

    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
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    Downloads: 25 This Week
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  • 13
    EN: Code created to show how is done the calculation of a CRC. It includes many different CRCs to choose from. This software was created to help people understand how is the CRC calculated and be able to see it in a practical way, it is also available to copy and use it for your own project. I hope it helps you. ES: Código creado para mostrar como se realiza el cálculo de un CRC. Con el mismo se incluyen varios CRCs que pueden ser escogidos. Este software se creó con el propósito de ayudar a la gente a entender como se hace el cálculo de un CRC de una manera más práctica y sencilla, también se puede copiar y aprovecharlo para otras aplicaciones. Espero que te sea util.
    Downloads: 7 This Week
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  • 14
    fHash

    fHash

    A files hash calculator for Windows and macOS.

    An open source files hash calculator for Windows and macOS. * MD5, SHA1, SHA256 and SHA512. * Drag & drop. * Integrated with context menu in Explorer/Finder. * Support Windows 7 and later. * Support macOS 13 and later, with universal binary. * Support Dark Mode. * English and Simplified Chinese UI. The icon "希" is from hash in Chinese "哈希".
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    Downloads: 8 This Week
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  • 15

    galculator

    galculator is a scientific calculator in algebraic mode and RPN

    galculator is a GTK 2 / GTK 3 based scientific calculator supporting algebraic mode as well as RPN. Features include arithmetic precedence handling, mathematical functions, different number bases (DEC, HEX, BIN, OCT) and angle bases (radiant, degree, and grad). Please note: This project page at sf.net reflects the state of the project up to August 2015. Beginning in September 2015, the project homepage was moved to http://galculator.mnim.org, with the source code repositories and issue trackers hosted at https://github.com/galculator/galculator.
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    Downloads: 4 This Week
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  • 16
    OpenDRO
    OpenDRO is an open source project to develop embedded software that runs on digital readouts (DROs) for lathes, mills, and other machine tools.
    Downloads: 7 This Week
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  • 17
    NOTE: Moved to https://github.com/vapier/pcalc Pcalc is a command line calculator handling HEX DEC OCT BIN. It can process a script, save variables to file, full math parser, parentheses, exponential, sin/cos, sqrt, date, inch/mm celsius/f, compound expressions ...
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    Downloads: 12 This Week
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  • 18
    OptionMatrix

    OptionMatrix

    Financial Derivatives Calculator with 171+ Models (Options Calculator)

    A real-time financial derivatives calculator supporting 171+ models from QuantLib, Financial Numerical Recipes in C++ and MetaOptions. Matrices of prices are created with iterating strikes and/or months. A strike control system can produce any strike. A generalized date engine can calculate re-occuring distances to any industry used expiration into the future. Spread engine with spread views. Models Supported: Black-Scholes, Merton-73, Black-76, Roll Geske Whaley, Garman KohlHagen, Jump Diffusion, Quanto, Vasicek Bond Option, Turnbull Wakeman Asian, TimeSwitchOption, Look Barrier, Bachelier, PartialTimeBarrier, GapOption, Extreme Spread Option, Simple Chooser, ComplexChooser, PartialFixedLB, Executive, CashOrNothing, Extendible Writer, OptionsOnOptions, BAWAmericanApprox, BSAmericanApprox, AssetOrNothing, Bisection, BAWbisection, BSbisection, Gfrench, Gcarry, Swapoption, Complex Chooser, Super Share, EquityLinkedFXO, Spread Approximation, BinaryBarrier and more
    Downloads: 3 This Week
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  • 19
    Getting your first mortgage? No, this isn't spam, its mort! A simple but powerful loan/mortgage calculator that also amortizes.
    Downloads: 10 This Week
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  • 20
    pfcalc is a pipe friction calculator using the Darcy-Weisbach equation. gpfcalc is a Gtk front-end for pfcalc. Qpfcalc is a Qt front-end for pfcalc.
    Downloads: 8 This Week
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  • 21
    HexTool is a simple yet effective calculator/tool; invaluable for people who work with Hex and Binary. Now you can convert between Hex, Binary and Decimal on the fly. No install needed: just unzip and run it!
    Downloads: 4 This Week
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  • 22

    cgtkcalc

    A simple calculator for complex number calculation.

    A simple scientific calculator for complex number calculation. It requires the GTK+ toolkit.
    Downloads: 4 This Week
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  • 23

    Simple Calendar

    Simple Calendar with extras

    So who wants to fire up Google, Outlook, or other gigantic program just for a quick look at a calendar? No one. Here is a simple calendar, a 6 month view, too simple really, but useful. A bit more useful since one can also find the # of days from a start day to an end day, inclusive. Also it can be used to show the resulting date once given a start date and +/- a number of days. Lastly, it can also set a simple alert for a date & time. This is a one shot alert, no repeat function. Version 2.0.2 supports four 'Methods' to schedule an alert; VBS, PowerShell 5.1, C, and PowerShell 7. The 'Method' to use can be selected, but defaults to C if no selection is made. An ini file has been added to store the 'Method' chosen. It can be run from a USB, just three files, nothing written to the registry, no phone home or telemetry. Simple calendar with a few 'extras' thrown in... Simple, free, small footprint, but hopefully useful. Version 2.0.2 released 8/7/2026
    Downloads: 3 This Week
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  • 24
    Console based notepad number cruncher makes calculations fast and simple, yet with ample features under the hood. With log turned on, you can record your session on-the-fly from any open instance of the program.
    Downloads: 2 This Week
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  • 25
    Numerical Systems Calculator

    Numerical Systems Calculator

    An arithmetic calculator for the most popular numerical systems.

    Have you ever imagined not having to do math to convert the various number systems and still make arithmetic calculations with different numerical systems in the same expression? That's what makes this application. You can mix decimal, binary, octal and hexadecimal arithmetic operations using the symbols "+, -, *, /,^,". You can put "e" to use Napier's constant, put "pi" to use pi constant and put a "!" in the of numerical system form to factorization. So let's start doing the math in an instant with this application and save the rest of the time for more useful things of interest.
    Downloads: 2 This Week
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